JP2010112281A - Exhaust emission control method and device of diesel internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise, and to shorten regeneration time, when regenerating a self-regeneration type filter device by manual operation in idling operation in stopping. <P>SOLUTION: In this exhaust emission control method of a diesel internal combustion engine 10 having a compression opening type engine brake means 42 mounted on a vehicle and the self-regeneration type filter device 30 arranged in an exhaust gas passage 26, and burning and removing PM deposited in a DPF by raising the temperature of the captured PM for oxidation by an oxidation catalyst 34 by capturing the PM in exhaust gas by the DPF 36, in idling operation when stopping the vehicle, a load of the diesel internal combustion engine 10 is increased in at least partial cylinders 12a, 12c and 12e by operating the compression opening type engine brake means 42 when a piston is positioned in the compression top dead center vicinity, and a fuel injection quantity of the other cylinders 12b, 12d and 12f is increased in response to an increase quantity of the load, and the oxidation reaction temperature of the PM is secured by the self-regeneration type filter device 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a diesel internal combustion engine that is mounted on a vehicle and includes a compression release type engine brake unit and an exhaust gas purification device that includes a self-regenerative type filter device. The present invention relates to an exhaust gas purification method and apparatus that enables self-regeneration of the self-regenerative filter device by manual operation during idling operation while stopped.

The amount of particulate matter (hereinafter referred to as “PM”) emitted from diesel internal combustion engines mounted on vehicles such as trucks and buses is being regulated more and more year by year together with NO _x , CO and HC. A technique for collecting PM by a filter called a diesel particulate filter (DPF; Diesel Particulate Filter) to reduce PM emission has been developed.

  By supplying high-temperature exhaust gas to this filter device, self-regeneration that can burn and remove PM trapped in the DPF becomes possible. In addition, there is a self-regenerating filter device that incinerates PM with high-temperature exhaust gas by providing an oxidation catalyst upstream of the DPF or by supporting the oxidation catalyst on the DPF.

The former self-regenerative filter device oxidizes NO in exhaust gas to NO ₂ by an oxidation catalyst carrying platinum or the like, and oxidizes PM trapped in the downstream DPF with this NO ₂ to produce CO _2. To be removed. The latter self-regenerative filter device is composed of a filter with an oxidation catalyst such as cerium oxide CeO ₂ and oxidizes and removes PM collected in the DPF by the oxidation catalyst. With these oxidation catalysts, PM can be oxidized and removed if the exhaust gas temperature is approximately 300 ° C. or higher.

  However, in idling operation, low load / low speed operation, etc., of the internal combustion engine, the exhaust gas temperature falls below the above temperature, so that the oxidation reaction by the oxidation catalyst is not promoted. Further, since NO is insufficient, the oxidation reaction does not proceed. For this reason, PM deposition progresses, causing clogging of the DPF.

  Therefore, post-injection (post-injection) of fuel is performed in the cylinder, fuel (HC) is supplied into the exhaust gas, fuel (HC) in the exhaust gas is burned (oxidized) with an oxidation catalyst, and the combustion heat generates an oxidation catalyst. By raising the temperature above the activation temperature, the PM collected in the DPF is oxidized and removed to regenerate the DPF.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2005-299418) or Patent Document 2 (Japanese Patent Laid-Open No. 2005-299438), the self-regenerative filter device is provided in the exhaust gas path of a diesel engine mounted on a vehicle. An exhaust gas purification system that performs post injection in a cylinder and oxidizes and removes PM trapped in the DPF is disclosed.

  Further, when excessive PM accumulates in the DPF, the vehicle may be stopped and manual regeneration may be performed at the driver's will. In this case, it is necessary to increase the engine speed in order to increase the exhaust gas temperature. For example, the engine speed is increased to 1500 rpm with respect to 650 rpm when idling.

As another exhaust gas temperature raising means, there is a method using an exhaust brake. In this method, the valve provided in the exhaust gas passage is closed to increase the exhaust gas pressure in the cylinder, and the engine load is increased to generate a braking force on the piston. By closing the exhaust gas passage in this way, the exhaust gas temperature is raised and the DPF self-regenerates.
Patent Document 3 (Japanese Patent Laid-Open No. 2005-220840) discloses a configuration of an exhaust brake when this method is employed.

JP 2005-299418A JP 2005-299438 A JP 2005-220840 A

  However, if the engine speed is increased for manual regeneration when the vehicle is stopped and the engine is idling, there is a problem that the exhaust gas temperature does not rise relative to the engine speed and the noise increases.

Further, in the method using the exhaust brake, as shown in FIG. 5, after the exhaust gas temperature is raised to 250 ° C. using the exhaust brake in the first stage, the fuel is post-injected in the second stage, Unburnt fuel (HC) is supplied to the self-regenerating filter device. Then, HC is burned (oxidized) to raise the exhaust gas temperature to the oxidation reaction temperature of the oxidation catalyst.
In the second stage, in order to burn the collected PM, it is necessary to supply fresh air to the exhaust gas path. Therefore, in the second stage, the exhaust gas path cannot be closed and the exhaust brake cannot be used.
In addition, there is a problem that fuel consumption that is not used for traveling of the vehicle increases due to post injection.

  In view of the problems of the prior art, the present invention reduces noise and reduces regeneration time when a self-regenerative filter device is regenerated by manual operation during idling while the vehicle is equipped with a diesel internal combustion engine. The purpose is to make it possible to shorten the fuel consumption.

In order to solve the above problems, an exhaust gas purification method for a diesel internal combustion engine of the present invention includes:
Mounted on a vehicle, comprising a compression-release type engine brake means, and a self-regenerative filter device provided in an exhaust gas path and comprising an oxidation catalyst and a DPF;
In the exhaust gas purification method for a diesel internal combustion engine, the exhaust gas temperature is raised by an oxidation reaction with an oxidation catalyst arranged on the upstream side of the DPF to oxidize and remove particulate matter in the exhaust gas captured by the DPF.
By increasing the load of the diesel internal combustion engine by activating the compression release type engine brake means when the piston is positioned near the compression top dead center during idling operation while the vehicle is stopped,
Corresponding to the increase in load, the fuel injection amount of the other cylinders is increased to raise the exhaust gas temperature, thereby securing the oxidation reaction temperature of the particulate matter in the self-regenerating filter device.

  The method of the present invention is directed to a diesel internal combustion engine mounted on a vehicle and provided with a compression release type engine brake means. In the compression process of a cylinder of a diesel internal combustion engine, when the piston reaches top dead center and the air in the cylinder is compressed, during normal operation, fuel is injected and burned at this stage, and the piston is pushed down with combustion energy. Get the rotational energy of the wheel.

  The compression release type engine brake means is known (see, for example, Japanese Patent Application Laid-Open No. 9-2105), and when the brake force is applied to the piston using the compression release type engine brake means, it is operated as follows. In the compression process, fuel is not injected, but the exhaust valve of the cylinder is opened to discharge the air in the cylinder. Therefore, air is not compressed in the cylinder and the kinetic energy of the piston is lost. Further, when the exhaust valve is closed in the expansion process after the piston has passed through the top dead center, the pressure in the cylinder becomes negative due to the lowering of the piston, which becomes a resistance against the lowering operation of the piston. By this operation, 85 to 90% of the required braking force can be secured.

In the method of the present invention, the compression-release type engine braking means is operated to at least some of the cylinders during idling while the vehicle is stopped. Thus, the exhaust gas temperature can be increased by increasing the load resistance of the diesel internal combustion engine and increasing the fuel injection amount of the other cylinders corresponding to the increase in load. Therefore, the exhaust gas temperature can be raised without increasing the rotational speed of the internal combustion engine.
Further, in the cylinder in which the compression release type engine brake means is operated, compressed high-temperature air is discharged to the exhaust gas passage. From these results, the exhaust gas temperature can be increased to 250 ° C. Then, post-injection can be performed next to ensure the oxidation reaction temperature of the oxidation catalyst of the self-regenerating filter device.

Thus, since the air temperature in the exhaust gas passage can be raised to 250 ° C. without increasing the rotational speed of the internal combustion engine, noise can be reduced.
Even in the second stage in which post injection is performed, the air temperature in the exhaust gas passage can be further increased by operating the compression release type engine brake means.

In the method of the present invention, it is preferable to operate the compression release type engine brake means in some cylinders and simultaneously perform fuel post-injection into the cylinders.
As a result, the unburned fuel is discharged into the exhaust gas path together with the compressed high-temperature air, so that the exhaust gas temperature can be increased efficiently due to the synergistic effect of the combustion of the high-temperature air and the unburned fuel. Therefore, the regeneration time can be shortened, fuel at the time of post-injection can be reduced, and fuel consumption can be improved.

Furthermore, since the compressed high-pressure air can be discharged to the exhaust gas passage, atomization of the post-injected fuel can be promoted. Therefore, the combustion reaction of unburned fuel (HC) can be promoted, and the exhaust gas temperature can be increased efficiently.
Further, since the post injection is performed when the piston is located near the top dead center, the injected fuel is received by the piston surface, and the fuel does not adhere to the inner wall of the cylinder. Therefore, there is no possibility that the fuel enters the crank chamber and enters the lubricating oil to cause oil dilution (dilution).

The exhaust gas purification apparatus for a diesel internal combustion engine of the present invention that can be directly used for carrying out the method of the present invention comprises:
Self-installed in a vehicle, with a compression-release type engine brake means and an oxidation catalyst disposed upstream of the DPF to oxidize and remove particulate matter in the exhaust gas that is trapped in the DPF by raising the exhaust gas temperature by an oxidation reaction In an exhaust gas purifying device for a diesel internal combustion engine comprising a regenerative filter device,
When the piston is positioned near the compression top dead center, the compression release type engine brake means is operated on at least some of the cylinders to increase the load of the diesel internal combustion engine, and the other cylinders correspond to the increased load. Provide a control device to increase the fuel injection amount,
The control device is configured to ensure the oxidation reaction temperature of the particulate matter in the self-regenerative filter device by operating the compression release type engine brake means by the control device and raising the exhaust gas temperature during idling operation while the vehicle is stopped. It is a thing.

In the device according to the present invention, when self-regeneration of the self-regenerative filter device is necessary during idling operation while the vehicle is stopped, the driver activates the control device, and at least some of the cylinders are compression-release engine brakes. Activate the means. Accordingly, the exhaust gas temperature can be raised by increasing the load of the diesel internal combustion engine and increasing the fuel injection amount in response to the increase of the load in the other cylinders.
Further, in the cylinder in which the compression release type engine brake means is operated, the compressed high-temperature air is discharged to the exhaust gas passage. From these results, the exhaust gas temperature can be raised to 250 ° C.

In the device of the present invention, it is preferable that the control device activates the compression release type engine brake means for a part of the cylinders and simultaneously performs post-injection of fuel into the cylinders.
Thereby, the oxidation reaction temperature of the oxidation catalyst of the self-regenerating filter device can be secured. Therefore, since it is not necessary to set the rotational speed of the internal combustion engine to a high speed, noise can be reduced.

In the device of the present invention, it is preferable that the control device applies the engine braking force by the compression release type engine braking means to a part of the cylinders, and at the same time, performs post-injection of fuel into the cylinders.
As a result, the unburned fuel is released into the exhaust gas path together with the compressed high-temperature air, and therefore the exhaust gas temperature can be increased efficiently by the combustion reaction of the unburned fuel. Therefore, the regeneration time can be shortened, fuel at the time of post-injection can be reduced, and fuel consumption can be improved.

In the device of the present invention, it is preferable that an operating switch for operating the compression release type engine brake means is provided in the control device by turning it on manually.
As a result, the manual regeneration operation can be activated by the driver operating the operation switch. Thus, manual regeneration can be performed only when the driver determines that it is necessary.

In the device of the present invention, the number of cylinders for operating the compression release type engine brake means may be determined based on the operation balance of the internal combustion engine or the effect of increasing the exhaust gas temperature.
The load resistance applied to the diesel internal combustion engine varies depending on the number of cylinders that operate the engine brake.
Therefore, it is possible to adjust the rotational speed of the diesel internal combustion engine during manual regeneration by adjusting the number of cylinders that operate the engine brake.

Further, in the device of the present invention, it is preferable to alternately arrange a cylinder that operates the compression release type engine brake means and a cylinder that does not operate the compression release type engine brake means.
During manual regeneration, the cylinders and exhaust gas passages have different temperatures between the cylinders that operate the engine brake and the cylinders that do not. For this reason, when the cylinders for operating the engine brake are concentrated in one place, thermal distortion occurs in the entire internal combustion engine. By adopting the above configuration, this thermal strain can be eliminated.

  According to the method of the present invention, an oxidation catalyst that is mounted on a vehicle and includes a compression-release type engine brake means, and a self-regenerative filter device that is provided in an exhaust gas path and includes an oxidation catalyst and a DPF, is disposed upstream of the DPF. In the exhaust gas purification method for a diesel internal combustion engine in which the exhaust gas temperature is raised by an oxidation reaction and the particulate matter in the exhaust gas captured by the DPF is oxidized and removed, the particulate matter in the exhaust gas is captured by the DPF filter In a method for purifying exhaust gas from a diesel internal combustion engine, the trapped particulate matter is oxidized and heated by an oxidation catalyst disposed upstream of the DPF filter, and particulate matter deposited on the DPF filter is burned and removed. When the piston is positioned near the compression top dead center in at least some of the cylinders during idling while the engine is stopped By actuating the rake means, the load on the diesel internal combustion engine is increased, the fuel injection amount of the other cylinders is increased corresponding to the increase in the load, and the exhaust gas temperature is increased, whereby the particles in the self-regenerative filter device Since the oxidation reaction temperature of the particulate matter is ensured, the exhaust gas temperature can be raised to 250 ° C. without increasing the rotational speed of the internal combustion engine, and therefore noise can be reduced. In addition, the regeneration time can be shortened, the fuel during post-injection can be reduced, and the fuel efficiency can be improved.

  According to the apparatus of the present invention, the exhaust gas temperature is increased by an oxidation reaction by the compression release engine brake means and the oxidation catalyst disposed on the upstream side of the DPF and captured by the DPF. And a self-regenerating filter device for oxidizing and removing particulate matter in the exhaust gas purifying device for a diesel internal combustion engine. A control device is provided to increase the load of the diesel internal combustion engine by operating the brake means, and to increase the fuel injection amount of the other cylinders corresponding to the increase in load, and the control device during idling operation while the vehicle is stopped By operating the compression release type engine brake means to increase the exhaust gas temperature, the oxidation reaction of particulate matter in the self-regenerating filter device is performed. Since it is configured to ensure the temperature, the enabling embodiment of the present invention method, it is possible to obtain the same effects as the method of the present invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an exhaust gas purification device for a diesel engine mounted on a vehicle. In FIG. 1, the diesel engine 10 includes six cylinders 12a to 12f. The head of each cylinder has an intake port provided with an intake valve 14, and an intake branch 22 is connected to the intake port. Moreover, it has an exhaust port provided with an exhaust valve 16, and an exhaust branch 24 is connected to the exhaust port. Further, an injector 18 for injecting fuel into the cylinder is provided.

The intake branch 22 of each cylinder is aggregated to form a main intake path 20, and the exhaust branch 24 of each cylinder is aggregated to form a main exhaust path 26.
A self-regenerative filter device 30 is interposed in the main exhaust passage 26. In the self-regenerating filter device 30, an oxidation catalyst 34 and a DPF 36 are arranged in order in the exhaust gas flow direction upstream side in a container 32 interposed in the main exhaust passage 26 so as to face the exhaust gas passage. An exhaust gas thermometer 33 is provided in the exhaust gas flow channel upstream of the oxidation catalyst 34. Further, a pressure gauge 38 is provided in the exhaust gas flow path in the DPF 36, and the pressure loss of the exhaust gas is detected by the pressure gauge 38, and the clogged state of the DPF 36 caused by the PM accumulation is detected by the detected value.

  The oxidation catalyst 34 is, for example, an oxidation catalyst carrying platinum or the like, and the DPF 36 is constituted by, for example, a ceramic honeycomb filter, or a filter made of ceramic or metal in the form of fibers.

The exhaust gas after the fuel is combusted in each cylinder 12 a-f reaches the self-regenerating filter device 30 through the exhaust branch passage 24 and the main exhaust passage 26. In the self-regenerating filter device 30, the oxidation catalyst 34 oxidizes NO in the exhaust gas to NO _2, and this NO ₂ oxidizes the PM collected in the downstream DPF 36 to remove it as CO ₂ . However, the oxidation reaction temperature of the oxidation catalyst 34 is 250 ° C. or higher. If the exhaust gas temperature is equal to or lower than the oxidation reaction temperature during idling operation while the vehicle is stopped, the oxidation reaction does not occur. Therefore, the self-regeneration of the DPF 36 becomes difficult.

  The diesel engine 10 includes an engine control unit (ECU) 40 that controls combustion of the diesel engine 10. The ECU 40 controls the injector 18 during operation to control the fuel injection timing and the injection amount.

  The diesel engine 10 includes compression release type engine brake means 42 that applies an engine brake force to each of the cylinders 12a to 12f. The engine brake means 42 operates as follows. That is, the fuel is not injected in the compression process, the exhaust valves 16 of the cylinders 12a to 12f are opened, and the air in the cylinders is discharged. Therefore, air is not compressed in the cylinder and the kinetic energy of the piston is lost.

  Further, when the exhaust valve 16 is closed in the expansion process after the piston has passed through the top dead center, the pressure in the cylinder becomes negative due to the lowering of the piston, which becomes a resistance against the lowering operation of the piston. That is, a braking force in the direction opposite to the normal piston rotation direction is generated. By this operation, auxiliary braking force can be secured.

  The hydraulic circuit for driving the exhaust valve 16 by the compression release type engine brake means 42 is divided into two systems. One hydraulic circuit 44 drives the exhaust valves 16 of the cylinders 12a, 12c and 12e, and the other hydraulic circuit 46 drives the exhaust valves 16 of the cylinders 12b, 12d and 12f. The two hydraulic circuits 44 or 46 are respectively provided with solenoid valves 48 or 50, and the ECU 40 controls the solenoid valves 48 or 50 to control the supply and discharge of the hydraulic oil. With this configuration, the exhaust valve 16 connected to the hydraulic circuit 44 or 46 operates separately.

  FIG. 2 shows the lift timing and the fuel injection timing of the exhaust valve 16 of the diesel engine 10 according to the present embodiment. FIG. 2 (a) shows a case of normal operation, and FIGS. 2 (b) and (c) show a case where the self-regenerative filter device 30 is manually regenerated while the vehicle is stopped and idling. (B) shows the first stage, and (c) shows the second stage.

During the normal operation shown in FIG. 2A, the main injection M of fuel is performed when the pistons of all the cylinders 12a to 12f are in positions near the compression top dead center. Then, the piston is lowered by the combustion of the fuel, and then the exhaust valve 16 is lifted and exhaust gas is discharged to the exhaust branch 24 in the process of moving the piston from the bottom dead center to the exhaust top dead center. Post injection P is performed in accordance with this timing, and combustion exhaust gas mixed with unburned fuel (HC) is discharged to the exhaust branch 24.
During normal operation, since the exhaust gas has a temperature of 250 ° C. or higher, the activation temperature of the oxidation catalyst 34 is obtained by burning (oxidizing) the unburned fuel mixed in the exhaust gas with the oxidation catalyst 34 and captured by the DPF 36. Self-regeneration that removes the collected PM by oxidation becomes possible.

In FIG. 2B, as the first stage of the manual regeneration operation, when the piston is at a position near the compression top dead center, the main injection M is stopped and the solenoid valve 48 is operated and connected to the hydraulic circuit 44. The exhaust valves 16 of the cylinders 12a, 12c and 12e are driven to open the exhaust branch 24 and increase the engine load.
As a result, the load resistance of the diesel engine 10 increases, and the exhaust gas temperature can be increased by increasing the fuel injection amount of the other cylinders 12b, 12d, and 12f in accordance with the increased load.

  Further, in the cylinders 12 a, 12 c and 12 e, compressed hot air is discharged to the exhaust branch 24. From these results, the exhaust gas temperature can be increased to 250 ° C. Therefore, the exhaust gas temperature can be raised without increasing the rotational speed of the diesel engine 10.

Next, as shown in FIG. 2 (c), as the second stage of manual regeneration operation, stop the main injection M, performs post-injection P ₁ from the injector 18 in place. By this operation, the cylinder air mixed with fuel is discharged to the exhaust branch 24. As a result, the fuel (HC) mixed in the air is oxidized by the oxidation catalyst 34, the exhaust gas temperature is increased by the reaction heat generated at that time, and the oxidation catalyst 34 can be increased to the oxidation reaction temperature. Then, the PM can be oxidized and removed by the oxidation reaction by the oxidation catalyst 34.

Note that post-injection, in place of the post-injection P ₁ performed when the piston is near top dead center, the piston may be subjected to post-injection P ₂ performed on the way towards the exhaust top dead center from the bottom dead center. However, the post-injection P _{1 performed} when the piston is near the top dead center can release the compressed hot air to the exhaust branch 24 more than the post-injection P ₂ , so that the heating effect of the oxidation catalyst 34 can be further improved. .

FIG. 3A schematically shows a PV diagram of the cylinders 12a to 12f when manual regeneration is performed. In FIG. 3 (a), P-V diagram ₁ on the left, a cylinder 12b do not operate the engine brake means, shows a P-V diagram of 12d and 12f, the right side of P-V diagram _{W 2} are each The PV diagram in the case of generating a normal rotational force by combustion without applying an engine load to the cylinders 12a to 12f is shown. Cylinder 12a, by applying the engine load to 12c and 12e, the cylinder 12b, it is necessary to perform more work _{A 1} only compensate for 12d at and 12f correspondingly. Further, in the cylinders 12a, 12c, and 12e, heat is added to the compressed air when the compressed air is discharged to the exhaust branch 24.

Accordingly, the cylinder 12b, and 12d and 12f workload _{A 1} of the work amount when the sum of the amount of heat added to the compressed air by the cylinder 12a, 12c and 12e are, for the normal idling operation to full cylinder 12a~f greater than A _2.
FIG. 3B shows this relationship on the basis of calorific value. That is, the cylinder 12b, 12d and 12f heat q1 and the cylinder 12a that occur in workload _{A 1} of the sum of the amount of heat Q which is added to the compressed air at 12c and 12e, the normal idling operation to full cylinder 12a~f the workload a ₂ is larger than the amount of heat q2 generated at which to.
Therefore, in the first stage of manual regeneration, the cylinders 12a to 12f are loaded, and the exhaust gas temperature can be raised at a low rotational speed.

  Next, an operation procedure at the time of manual regeneration will be described with reference to FIG. In FIG. 4, it is assumed that a manual regeneration request for the self-regenerative filter device 30 is made in step 1 during idling while the vehicle is stopped. Whether or not manual regeneration is necessary can be determined by means such as a flashing alarm lamp (not shown) when the pressure loss detected by the pressure gauge 38 exceeds a limit value.

  Therefore, the driver turns on the operation switch 43 (step 2). When the operation switch 43 is turned on, the ECU 40 controls the operation state of the diesel engine 10 to a purification device that is optimal for manual regeneration (step 3). Next, as shown in FIG. 2B, the ECU 40 stops the main injection M, operates the solenoid valve 48 of the hydraulic circuit 44, and opens the exhaust valves 16 of the cylinders 12a, 12c and 12e (step 4). ). As a result, an engine load is applied to the cylinders 12a, 12c, and 12e.

When an engine load is applied to the cylinders 12a, 12c, and 12e, the load resistance of all the cylinders 12a to 12f increases. Since the fuel injection amount of the cylinders 12b, 12d, and 12f increases by the increase in the negative pressure resistance, the exhaust gas temperature rises. Further, in the cylinders 12a, 12c, and 12e, the high-temperature air compressed in the compression process is discharged to the exhaust branch 24.
As a result, the temperature of the main exhaust passage 26 can be set to 250 ° C. or higher. Therefore, the exhaust gas temperature can be raised to 250 ° C. or higher while suppressing the rotation speed of all cylinders and suppressing noise.

Next, as a second stage, as shown in FIG. 2 (c), post-injection P ₁ (or P ₂ ) is performed, unburned fuel is burned (oxidized) by the oxidation catalyst 34, and the oxidation heat is used as the oxidation catalyst. Since the temperature of 34 is raised to the activation temperature or higher, the PM collected in the DPF 36 can be oxidized and removed to regenerate the DPF 36 itself.

As described above, according to the present embodiment, the exhaust gas temperature of the cylinders 12a to 12f can be increased using the compression release type engine brake means 42 during idling while the vehicle is stopped. Regeneration processing of the filter device 30 is enabled.
Further, since the load on the cylinders 12a to 12f is increased and reproduction is possible at a low rotational speed, noise can be reduced.

  Further, in the cylinders 12a, 12c and 12e for operating the compression release type engine brake means 42, the exhaust valve 16 is opened when the piston is located near the compression top dead center, and the compressed high temperature air is supplied to the main exhaust passage 26. Therefore, the oxidation catalyst 34 can be efficiently heated.

Further, performs post-injection P ₁ when the piston is positioned near the compression top dead center, so along with the compressed high-pressure air discharged into the exhaust branch passage 24, the cylinder 12a, 12c, the atomization of the injected fuel in the 12e Therefore, since the oxidation reaction in the self-regenerating filter device 30 can be promoted, the exhaust gas temperature can be increased efficiently. As a result, the regeneration time of the DPF filter 36 can be shortened, post-injected fuel can be saved, and fuel consumption can be improved.
Further, since the post injection is performed when the piston is located near the top dead center, the injected fuel is received by the piston surface, and the fuel does not adhere to the inner walls of the cylinders 12a, 12c, and 12e. Therefore, there is no possibility that the fuel enters the crank chamber and enters the lubricating oil to cause oil dilution (dilution).

In addition, since the operation switch 43 is provided and the manual regeneration is performed when the driver turns on the operation switch 43, the operation is facilitated and the manual regeneration can be performed only when the driver determines that it is necessary. .
Further, the cylinders 12a, 12c and 12e for operating the engine brake and the cylinders 12b, 12d and 12f for not operating the engine brake are alternately arranged so that the former cylinder is not concentrated in one place. As a result, thermal distortion does not occur.

In the above-described embodiment, the engine brake means is operated for the three cylinders 12a, 12c, and 12e. However, if the number of cylinders that operate the engine brake means is increased, the diesel engine 10 during idling operation is correspondingly increased. The number of rotations can be reduced, and the degree of noise can be reduced corresponding to the reduction in the number of rotations.
Thus, the number of cylinders for operating the engine brake means can be appropriately set in consideration of the engine speed.

  According to the present invention, the self-regeneration of the exhaust gas purification device of a diesel internal combustion engine mounted on a vehicle can be achieved with low noise and low fuel consumption.

It is a lineblock diagram of the diesel engine concerning one embodiment of the present invention. It is a diagram which shows the lift operation and fuel injection timing of the exhaust valve which concern on the said embodiment. It is a PV diagram which shows typically operation of a cylinder concerning the embodiment. It is a flowchart which shows the operation procedure of the manual reproduction | regeneration which concerns on the said embodiment. It is a diagram which shows the conventional manual regeneration method.

Explanation of symbols

10 Diesel engine 12a-f Cylinder
14 Intake Valve 16 Exhaust Valve 18 Injector 24 Exhaust Branch 26 Main Exhaust Path 30 Self-Regenerative Filter Device 34 Oxidation Catalyst 36 DPF
40 ECU (control device)
42 compression release type engine brake means 43 operates switches 44 hydraulic circuits 48 and 50 the solenoid valve M main injection P _{1, P 2} post injection

Claims (7)

Mounted on a vehicle, comprising a compression-release type engine brake means, and a self-regenerative filter device provided in an exhaust gas path and comprising an oxidation catalyst and a DPF;
In the exhaust gas purification method for a diesel internal combustion engine, the exhaust gas temperature is raised by an oxidation reaction with an oxidation catalyst arranged on the upstream side of the DPF to oxidize and remove particulate matter in the exhaust gas captured by the DPF.
By increasing the load of the diesel internal combustion engine by activating the compression release type engine brake means when the piston is positioned near the compression top dead center during idling operation while the vehicle is stopped,
The oxidation reaction temperature of the particulate matter in the self-regenerative filter device is secured by increasing the fuel injection amount of the other cylinders corresponding to the increase in load and increasing the exhaust gas temperature. An exhaust gas purification method for a diesel internal combustion engine.   2. The exhaust gas purification method for a diesel internal combustion engine according to claim 1, wherein the compression-release type engine brake means is operated for the some cylinders, and at the same time, the fuel is post-injected into the cylinders. . Self-installed in a vehicle, with a compression-release type engine brake means and an oxidation catalyst disposed upstream of the DPF to oxidize and remove particulate matter in the exhaust gas that is trapped in the DPF by raising the exhaust gas temperature by an oxidation reaction In an exhaust gas purifying device for a diesel internal combustion engine comprising a regenerative filter device,
When the piston is positioned near the compression top dead center, the compression release type engine brake means is operated on at least some of the cylinders to increase the load of the diesel internal combustion engine, and the other cylinders correspond to the increased load. Provide a control device to increase the fuel injection amount,
The control device is configured to ensure the oxidation reaction temperature of the particulate matter in the self-regenerative filter device by operating the compression release type engine brake means by the control device and raising the exhaust gas temperature during idling operation while the vehicle is stopped. An exhaust gas purification apparatus for a diesel internal combustion engine, characterized in that:   4. The diesel engine according to claim 3, wherein the controller is configured to operate the compression release type engine brake means in the some cylinders and simultaneously perform fuel post-injection into the cylinders. 5. An exhaust gas purification device for an internal combustion engine.   4. The exhaust gas purification apparatus for a diesel internal combustion engine according to claim 3, wherein an operation switch for operating the compression release type engine brake means is provided in the control device by turning it on manually.   4. The exhaust gas purification apparatus for a diesel internal combustion engine according to claim 3, wherein the number of cylinders for operating the compression release type engine brake means is determined based on an operation balance of the internal combustion engine or an effect of increasing the exhaust gas temperature.   The exhaust gas purification apparatus for a diesel internal combustion engine according to claim 3, wherein a cylinder for operating the compression release type engine brake means and a cylinder for not operating the compression release type engine brake means are alternately arranged.

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