JP2003097252A - Exhaust gas purifier of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas purifier of an internal combustion engine capable of obtaining an excellent reduction efficiency of NOx. SOLUTION: In a diesel engine 1, while communicating the inside of a combustion chamber 11A and an exhaust passage 30 with an exhaust valve 14 during intake process, an exhaust throttle valve 61 is activated by an exhaust flow rate controller 70 so as to adjust exhaust gas quantity flowing through the exhaust passage 30. As a result, even if the differential pressure between the exhaust side and the intake side changes, the displacement recirculated into the combustion chamber 11A can be controlled. The optimum exhaust gas recirculation quantity is set with respect to the operating situation of the diesel engine 1. An opening of the exhaust throttle valve 61 is adjusted so as to obtain the set exhaust gas recirculation quantity. Therefore, even if the intake pressure is higher than the exhaust pressure, the set quantity of exhaust gas is recirculated in the combustion chamber 11A by increasing the exhaust pressure with respect to the intake pressure. By so doing, the optimum quantity of exhaust gas is returned into the combustion chamber 11A, whereby an excellent reduction efficiency of NOx by the inside EGR is achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to an exhaust gas purifying apparatus for an internal combustion engine for reducing NOx in exhaust gas discharged from the internal combustion engine.

[0002]

BACKGROUND ART Conventionally, exhaust gas recirculation (hereinafter referred to as EGR) that supplies a part of exhaust gas into a combustion chamber in order to reduce nitrogen oxides, so-called NOx, contained in exhaust gas of an internal combustion engine.
Is used. According to such EGR, the combustion air (intake air) supplied to the internal combustion engine is mixed with a gas (exhaust gas) having a large heat capacity such as carbon dioxide and water vapor, and the heat capacity of the air is increased. The temperature drops,
Generation of NOx is suppressed.

The EGR includes a so-called external EGR that supplies the exhaust gas in the exhaust passage into the intake passage and a so-called internal EGR that directly returns the exhaust gas in the exhaust passage into the combustion chamber. Of these, the internal EGR will be specifically described. The internal EGR is disposed between the combustion chamber and the exhaust passage at the time when the intake valve disposed between the combustion chamber and the intake passage of the internal combustion engine is open, that is, during the intake stroke. By opening the exhaust valve, the opening timing of the intake valve and the opening timing of the exhaust valve are overlapped, so that the intake and exhaust of the intake and exhaust in the combustion chamber are reduced during the period when the cylinder internal pressure is lower than the intake and exhaust pressures. It becomes possible to capture both.

[0004]

However, in the internal EGR as described above, the amount of exhaust gas (exhaust gas recirculation amount) taken into the combustion chamber due to the differential pressure between the intake side and the exhaust side.
Therefore, there is a problem that an arbitrary amount of exhaust gas cannot be returned to the combustion chamber and an optimal exhaust gas recirculation amount according to the operating condition of the internal combustion engine cannot be obtained. Therefore, the internal E
It becomes difficult to improve the efficiency of reducing NOx in exhaust gas by GR.

An object of the present invention is to provide an exhaust gas purifying apparatus for an internal combustion engine which can improve NOx reduction efficiency.

[0006]

In order to achieve the above-mentioned object, an exhaust gas purifying apparatus for an internal combustion engine according to the present invention is provided with an intake air for supplying intake air to the combustion chamber of the internal combustion engine. And an exhaust passage for discharging exhaust gas from the combustion chamber, and an exhaust passage opening / closing means capable of connecting / disconnecting the combustion chamber and the exhaust passage, and a downstream of the exhaust passage from the exhaust passage opening / closing means. And an exhaust flow rate adjusting means capable of adjusting the amount of exhaust flowing through the exhaust passage by changing the opening, and the exhaust passage opening / closing means during the intake stroke for intake into the combustion chamber. The combustion chamber and the exhaust passage are communicated with each other. Here, as the exhaust passage opening / closing means, an exhaust valve that connects the combustion chamber and the exhaust passage during the exhaust stroke may be used,
Further, a valve member different from the exhaust valve may be used.

According to the present invention, during the intake stroke, the exhaust passage opening / closing means makes the combustion chamber communicate with the exhaust passage, and
Since the exhaust flow rate adjusting means adjusts the amount of exhaust gas flowing through the exhaust passage, even if the differential pressure between the exhaust side and the intake side fluctuates, the magnitude of the exhaust pressure relative to the intake pressure can be adjusted by appropriately adjusting the opening of the exhaust flow rate adjusting means. The desired amount of exhaust gas can be returned (recirculated) to the combustion chamber.
Therefore, if the optimal exhaust gas recirculation amount is set for the operating condition of the internal combustion engine and the opening degree of the exhaust gas flow rate adjusting means is controlled so that the set exhaust gas recirculation amount is obtained, even if the intake pressure is higher than the exhaust pressure. Even if it is higher, it is possible to raise the exhaust pressure with respect to the intake pressure, so that the set amount of exhaust gas is returned to the combustion chamber, and the optimum amount according to the operating conditions of the internal combustion engine is obtained. The exhaust gas can be returned to the combustion chamber. Thus, by always returning the optimum amount of exhaust gas to the combustion chamber, it is possible to improve the NOx reduction efficiency by the internal EGR.

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, it is desirable that an exhaust post-treatment device for purifying inflowing exhaust gas is installed in the middle of the exhaust passage. Here, as an exhaust aftertreatment device, a diesel particulate filter (hereinafter, DPF (Diesel Particulate F
exhaust aftertreatment device having a NOx reduction catalyst, an exhaust aftertreatment device having a NOx occlusion reduction catalyst, an exhaust aftertreatment device having an oxidation catalyst, and an exhaust aftertreatment device having a three-way catalyst. Either can be adopted.

Thus, by incorporating the exhaust aftertreatment device in the exhaust passage of the internal combustion engine, NOx in the exhaust gas can be reduced by the internal EGR in the exhaust gas purifying device and the exhaust aftertreatment device can purify the exhaust gas. Since it can be done, the exhaust gas can be made even cleaner.
Further, the exhaust flow rate adjusting means can appropriately adjust the amount of exhaust gas flowing through the exhaust passage to control the exhaust pressure and exhaust gas recirculation amount that affect the exhaust temperature, so that the exhaust temperature can be raised or lowered. The exhaust gas temperature can be kept within a temperature range in which the activity of the exhaust post-treatment device is high, and the exhaust gas purification efficiency can be improved.

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, when an exhaust flow rate control valve capable of adjusting the amount of exhaust gas flowing through the exhaust passage by changing the opening of the valve is used as the exhaust flow rate control means, Since the flow control valve is newly installed in the middle of the exhaust passage of the internal combustion engine, the exhaust flow control valve can be provided at any position without being restricted by the design and structure of the internal combustion engine. Therefore, the equipment attached to the exhaust flow rate control valve (equipment such as an actuator for driving the exhaust flow rate control valve) can be installed at any position, so that the exhaust flow rate control valve and attached equipment can be installed in an empty space of the internal combustion engine. In this case, it is possible to avoid lowering the degree of freedom in designing the internal combustion engine.

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, the exhaust flow rate adjusting means serves to obtain a driving force by rotating the turbine with exhaust gas to supercharge the internal combustion engine, and the inlet area of the turbine is When the variable turbine turbocharger that can be changed is adopted, it is possible to control the rotational speed of the turbine by appropriately adjusting the inlet area of the turbine to adjust the exhaust flow rate through the variable turbocharger. Becomes The exhaust pressure can be adjusted by adjusting the inlet area of the turbine, and the boost pressure of the compressor can be adjusted by adjusting the rotational speed of the turbine, so that the balance between the intake pressure and the exhaust pressure can be adjusted. Easy and reliable. Therefore, the amount of exhaust gas recirculated into the combustion chamber can be controlled more reliably.

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, a rotational speed detecting means for detecting the rotational speed of the internal combustion engine, and a load detecting means for detecting the load of the internal combustion engine,
A storage unit that stores a map indicating the opening degree of the exhaust flow rate control unit that obtains at least one of the optimum exhaust gas recirculation amount and the optimum exhaust gas temperature with respect to the rotation speed of the internal combustion engine and the load of the internal combustion engine. And a control unit that adjusts the exhaust flow rate of the exhaust passage according to the operating state of the internal combustion engine based on the map stored in the storage unit.

The optimum exhaust gas recirculation amount is an exhaust gas recirculation amount set in consideration of the NOx reduction rate, the soot generation rate, etc., which change due to the decrease in the maximum combustion temperature. The optimum exhaust gas temperature is an exhaust gas temperature that is set in consideration of the durability of the diesel engine 1 against the exhaust gas temperature rise due to exhaust gas recirculation. Here, when an exhaust aftertreatment device is provided in the exhaust gas purification device according to the present invention,
The optimum exhaust temperature is set in consideration of the temperature range in which the exhaust post-treatment device is activated.

According to the present invention, the opening degree of the exhaust flow rate adjusting means for obtaining at least one of the optimum exhaust gas recirculation amount and the optimum exhaust gas temperature with respect to the rotational speed and the load of the internal combustion engine is obtained by experiments, calculations and the like. For example, it is possible to obtain a map showing the optimum opening degree of the exhaust flow rate adjusting means according to the operating condition of the internal combustion engine. By providing a storage unit that stores the above-mentioned map and a control unit that adjusts the exhaust flow rate of the exhaust passage based on this map, at least one of the optimum exhaust gas recirculation amount and the optimum exhaust temperature can be obtained. As described above, the opening degree of the exhaust flow rate adjusting means can be adjusted quickly.

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, temperature detecting means for detecting at least one of the temperature of the exhaust aftertreatment device and exhaust temperature, and control means for controlling the operation of the exhaust flow rate adjusting means. When the temperature detected by the temperature detecting means exceeds a predetermined temperature, the control means increases the opening degree of the exhaust flow rate adjusting means, and the temperature detected by the temperature detecting means is the predetermined temperature. If not, it is desirable to reduce the opening degree of the exhaust flow rate adjusting means. Here, the control means according to the invention of claim 6 may be provided integrally with the control means according to the invention of claim 5, or it may be provided separately. Good. As the predetermined temperature,
It may indicate a certain one temperature value, or may indicate a predetermined temperature range.

According to the present invention, when the temperature detected by the temperature detecting means exceeds the predetermined temperature and the opening degree of the exhaust flow rate adjusting means is increased, the exhaust pressure is reduced and the exhaust gas recirculation amount is also reduced. Can be lowered. On the other hand, when the temperature detected by the temperature detecting means does not reach the predetermined temperature, if the opening degree of the exhaust flow rate adjusting means is reduced,
Since the exhaust pressure increases and the exhaust gas recirculation amount also increases, the exhaust temperature can be increased. Therefore, the exhaust temperature can always be maintained at a substantially predetermined temperature, and if such a predetermined temperature is set in correspondence with the temperature range in which the exhaust post-treatment device is activated, the exhaust after-treatment device is exhausted. It becomes possible to maintain good gas purification efficiency.

In such an exhaust gas purifying apparatus for an internal combustion engine, when the temperature detected by the temperature detecting means exceeds a predetermined temperature, the control means increases the higher the temperature detected by the temperature detecting means. When the opening degree of the exhaust flow rate adjusting means is increased and the temperature detected by the temperature detecting means does not reach the predetermined temperature, the lower the temperature detected by the temperature detecting means is, the more the exhaust flow rate adjusting means is. It is desirable to reduce the opening degree.

With this configuration, when the temperature detected by the temperature detecting means exceeds the predetermined temperature, the higher the temperature, the larger the opening of the exhaust flow rate adjusting means.
When the temperature is considerably high, the exhaust temperature is greatly reduced by considerably increasing the opening degree of the exhaust flow rate adjusting means, and the exhaust temperature can be quickly reduced to a predetermined temperature. On the other hand, when the temperature is a little high, the exhaust gas temperature is decreased a little by increasing the opening degree of the exhaust gas flow rate adjusting means, and it is possible to prevent the exhaust gas temperature from being excessively decreased and falling below the predetermined temperature. Further, when the temperature detected by the temperature detecting means does not reach the predetermined temperature, the lower the temperature is, the smaller the opening of the exhaust flow rate adjusting means is made.Therefore, when the temperature is considerably low, the exhaust flow rate adjusting means is opened. By making the degree considerably smaller, the exhaust gas temperature is greatly increased, and it becomes possible to quickly raise the exhaust gas temperature to a predetermined temperature. On the other hand, when the temperature is a little low, it is possible to prevent the exhaust temperature from being raised slightly and exceeding the predetermined temperature by slightly raising the exhaust temperature by slightly reducing the opening degree of the exhaust flow rate adjusting means. .

In the exhaust gas purifying apparatus for an internal combustion engine of the present invention, it is desirable that the opening of the exhaust flow rate adjusting means be substantially fully opened when the operating state of the internal combustion engine is a rapid acceleration state. As described above, when the internal combustion engine is performing rapid acceleration, if the opening of the exhaust flow rate adjusting means is substantially fully opened, the exhaust pressure with respect to the intake pressure becomes small, and intake air easily enters the combustion chamber. A large amount of intake air is supplied to. Therefore, it is possible to secure the engine output required for the rapid acceleration, and thus it is possible to avoid impairing the rapid acceleration performance of the internal combustion engine.

In the exhaust gas purifying apparatus for an internal combustion engine according to the present invention, the internal combustion engine is rotated by an intake valve capable of connecting and disconnecting the combustion chamber and the intake passage, and combustion and explosion of fuel in the combustion chamber. And a driven crankshaft, the intake valve communicates the combustion chamber with the intake passage during the intake stroke, and the crank angle at the end of the intake stroke is the top dead center of the crank angle. The exhaust passage opening / closing means is set to 150 ° or more and 180 ° or less afterward, and the exhaust passage opening / closing means connects the combustion chamber and the exhaust passage to the exhaust passage at any time during the period from the latter half of the intake stroke to immediately after the end of the intake stroke. It is desirable to communicate. In the present invention, the end timing of the intake stroke is made earlier than usual, and the combustion chamber and the exhaust passage are communicated with each other at any time during the period from the latter half of the intake stroke to immediately after the end of the intake stroke.
When the negative pressure in the combustion chamber (pressure below atmospheric pressure) is large,
It is possible to increase the resistance on the intake side and decrease the resistance on the exhaust side. As a result, the maximum amount of exhaust gas that can be recirculated to the combustion chamber can be increased, and the upper limit value of the exhaust gas recirculation amount that can be controlled by adjusting the opening degree of the exhaust gas flow rate adjusting unit can be increased.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 shows a system according to a first embodiment of the present invention. This system includes a diesel engine 1 as an internal combustion engine and exhaust gas provided in the diesel engine 1. The purification device 2 is provided.

First, the outline of the system will be described.
The diesel engine 1 is an internal combustion engine that generates a driving force by injecting fuel into compressed high temperature air to self-ignite, and a plurality of cylinders 11 (only one cylinder 11 is shown in FIG. 1, Other cylinders are omitted.), An intake passage 20 for intake air to the cylinder 11, an exhaust passage 30 for exhaust air of the cylinder 11, and an exhaust passage for the diesel engine 1. A supercharger 41 that compresses intake air to supply fuel and an engine controller 50 that controls the operation of the diesel engine 1 are provided. The exhaust gas purification device 2 includes an exhaust throttle valve 61 and an exhaust aftertreatment device 6 as an exhaust flow rate control valve installed in the exhaust passage 30 of the diesel engine 1.
2 and an exhaust flow controller 70 that controls the operation of the exhaust throttle valve 61.

Next, details of the system will be described.
In the engine body 10 of the diesel engine 1, a combustion chamber 11A is formed inside each cylinder 11, and an intake passage 20 and an exhaust passage 30 are connected to the combustion chamber 11A. In addition, in the upper part of the cylinder 11,
A cylinder head 12 that forms the top wall of the combustion chamber 11A is provided, and an intake valve 13, an exhaust valve 14 as an exhaust passage opening / closing means, and a fuel injection nozzle 15 are mounted on the cylinder head 12.

The intake valve 13 includes a combustion chamber 11A and an intake passage 20.
Is arranged between the combustion chamber 11 and
It is possible to connect / disconnect between A and the intake passage 20. The exhaust valve 14 is disposed between the combustion chamber 11A and the exhaust passage 30 and moves up and down to move the combustion chamber 11A.
It is possible to connect / disconnect between and the exhaust passage 30. The driving force for vertically moving the intake valve 13 and the exhaust valve 14 is obtained by rotationally driving a cam shaft (not shown) provided in the engine body 10. Although not shown, the camshaft is rotationally driven by transmitting the rotational driving force of the crankshaft via a timing gear.

Here, in the present embodiment, the intake valve 13
The opening / closing operation (up / down operation) of the exhaust valve 14 is performed at the timings shown in the graphs of FIGS. In these graphs of FIGS. 2 to 4, the vertical axis indicates the intake valve 13
And the valve lift amount (elevation amount) of the exhaust valve 14, and the horizontal axis indicates the rotation angle of the crankshaft (so-called crank angle). Further, in the present embodiment, the diesel engine 1 is a four-cycle (four-stroke) engine in which one cycle is completed in four strokes of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

2 to 4, the intake valve 13 rises and opens during the intake stroke, as shown by the alternate long and short dash line, and connects the interior of the combustion chamber 11A with the intake passage 20. The lift timing (opening timing) and the lift amount (opening degree) of the intake valve 13 are appropriately set according to the cam lobe shape of the cam shaft that drives the intake valve 13.

On the other hand, the exhaust valve 14 rises and opens during the exhaust stroke, as shown by the solid curve C1, and again rises and opens during the intake stroke, as shown by the solid curve C2, inside the combustion chamber 11A. Communicates with the exhaust passage 30. Similar to the intake valve 13, the lift timing and the lift amount of the exhaust valve 14 are appropriately set according to the cam lobe shape of the cam shaft that drives the exhaust valve 14. here,
In the present embodiment, the lift of the exhaust valve 14 indicated by the curve C2 is also performed by rotationally driving the cam shaft.
For this reason, the cam lobe shape of the cam shaft is a shape in which a convex portion is further formed on the cam lobe having a normal shape (shape such as an elliptical shape, an egg shape, or a diaper shape). The lift of the exhaust valve 14 indicated by the curve C2 is not limited to the lift by the cam shaft, but may be performed by an actuator such as a hydraulic cylinder.

In the present embodiment, the exhaust stroke, intake stroke,
To specifically describe the lift timing of the exhaust valve 14 indicated by the curve C2, the crank angle CA1 at the start timing of the exhaust stroke is −240 ° or more and −225 ° or less before the top dead center (TDC) of the crank angle. The crank angle CA2 is set and the end time thereof is set to 15 ° or more and 30 ° or less after the top dead center of the crank angle. Crank angle CA at the start of the intake stroke
3 is -30 ° or more before the top dead center of the crank angle -20
Crank angle C at the end of the crank angle setting
A4 is 150 ° or more after the top dead center of the crank angle 21
It is set to 0 ° or less. The crank angle CA5 of the lift start timing of the exhaust valve 14 shown by the curve C2 is set to 60 ° or more and 150 ° or less after the top dead center of the crank angle, and the crank angle CA6 of the lift end timing is
The crank angle is set to 150 ° or more and 210 ° or less after the top dead center.

That is, for example, as shown in FIG. 2, in the intake stroke, the crank angle CA4 at the end timing is
The crank angle is set to an angle larger than 180 ° which is the bottom dead center (BDC), and in the lift of the exhaust valve 14 shown by the curve C2, the crank angle CA5 at the lift start timing is set to the latter half of the intake stroke, The crank angle CA6 at the end timing of the lift may be substantially matched with the crank angle CA4 at the end timing of the intake stroke. Also,
For example, as shown in FIG. 3, in the intake stroke, the crank angle CA4 at the end timing is set to an angle larger than 180 ° which is the bottom dead center (BDC) of the crank angle, and the exhaust valve 14 indicated by the curve C2 is changed. In the lift, the crank angle CA5 at the lift start timing may be set to the first half of the intake stroke, and the crank angle CA6 at the lift end timing may be set to a timing earlier than the end timing of the intake stroke. Further, for example, as shown in FIG. 4, in the intake stroke, the crank angle CA4 at the end time is set to 180 ° which is the bottom dead center (BDC) of the crank angle, and the lift of the exhaust valve 14 shown by the curve C2 is set. The crank angle CA5 at the lift start timing is set to the latter half of the intake stroke, and the crank angle CA6 at the lift end timing is set to the crank angle C at the end timing of the intake stroke.
You may make it substantially match with A4.

As described above, when the intake valve 13 and the exhaust valve 14 are opened and closed at the timings shown in FIGS. 2 to 4, the resistance on the intake side becomes large and the inside of the combustion chamber (cylinder) becomes less than the intake pressure. Since the exhaust valve 14 shown by the curve C2 is lifted at a time close to the end of the intake stroke at which the pressure is set to, the exhaust gas is partially burned from the exhaust passage 30 kept at least at the cylinder internal pressure or higher. It becomes possible to return it to the chamber 11A. That is, internal EGR is possible. In particular, if the intake valve 13 and the exhaust valve 14 are opened and closed at the timings illustrated in FIG. 4, the intake air is intaken while the crankshaft angle has not reached bottom dead center, that is, when the negative pressure in the combustion chamber 11A is large. Since the valve 13 is closed to increase the resistance on the intake side and the lift on the exhaust valve 14 shown by the curve C2 is performed to reduce the resistance on the exhaust side, a large amount of exhaust gas recirculation is obtained.

The fuel injection nozzle 15 injects and supplies the fuel pressurized by a fuel injection pump (not shown) into the cylinder 11. In the present embodiment, as the fuel injection device of the diesel engine 1, the fuel injection device having the above-described fuel injection nozzle 15 and the fuel injection pump with a governor (not shown) is adopted. The fuel injection amount / fuel injection timing from the fuel injection nozzle 15 to the cylinder 11 is determined by the operation of the fuel injection pump, and the operation of the fuel injection pump is controlled by the engine controller 50 via the governor.

The intake passage 20 includes an intake port 21 formed in the cylinder head 12 and an intake manifold (not shown) connected to each cylinder 11 via the intake port 21. A compressor 41A of the supercharger 41 and an intercooler 42 that cools the intake air are provided in the intake passage 20. The exhaust passage 30 has an exhaust port 3 formed in the cylinder head 12.
1 and an exhaust manifold (not shown) connected to each cylinder 11 via the exhaust port 31. An exhaust turbine 41B of the supercharger 41, an exhaust throttle valve 61 of the exhaust gas purification device 2 and an exhaust aftertreatment device 62 are provided in the exhaust path 30.

As described above, the supercharger 41 has the intake passage 2
Compressor 41A arranged at 0 and exhaust passage 30
Has an exhaust turbine 41B disposed at In the supercharger 41, the exhaust turbine 41B is rotated by utilizing the exhaust gas, whereby the compressor 41A is rotationally driven to compress the intake air, whereby the diesel engine 1 is supercharged.

The exhaust throttle valve 61 of the exhaust gas purification device 2 is
It is installed in the exhaust passage 40 downstream of the installation position of the exhaust turbine 41B of the supercharger 41 and upstream of the installation position of the exhaust aftertreatment device 62. In this exhaust throttle valve 61,
An actuator (actuator such as a motor or a cylinder) 61A for opening and closing the exhaust throttle valve 61 is provided. The exhaust flow rate control valve is not limited to the throttle valve (throttle valve), but various valves such as a butterfly valve and a gate valve can be adopted, and any valve capable of adjusting the flow rate of the exhaust gas flowing through the exhaust passage 30 can be used. It may be a valve. The actuator 61A is the exhaust flow controller 7
0, the operation of which is controlled by the exhaust flow controller 70. The exhaust flow controller will be described in detail later. With such a configuration, by appropriately controlling the operation of the actuator 61A, the opening degree of the exhaust throttle valve 61 is adjusted, and the flow rate of exhaust gas passing through the exhaust passage 30 per unit time is adjusted.

As shown in FIG. 5, the exhaust post-treatment device 62 is provided with a substantially columnar carrier 62A, which is a carrier 62A.
The structure has a large number of small holes 621 in a honeycomb shape. The small holes 621 are formed from the inflow side end surface 622 to the outflow side end surface 6
They are communicated toward the 23 side, that is, along the axial direction of the carrier 62A, and the cross section thereof is formed in a polygonal shape (hexagonal shape in this embodiment). The carrier 62A is made of cordierite, ceramics such as silicon carbide, or metal such as stainless steel or aluminum, and the material thereof is appropriately determined according to the application of the carrier 62A.

When the exhaust aftertreatment device 62 is a DPF, the numerous small holes 621 of the carrier 62A are formed on the outflow side end face 62.
It is divided into a small hole 621 which functions as an inflow side flow path by plugging the 3 side and a small hole 621 which functions as an outflow side flow path by plugging the inflow side end face 622 side. These flow paths are arranged in a staggered pattern. The boundary wall portion of each flow path (small hole 621) has a random porous shape, and particulates (for example, soot, mist of unburned fuel or lubricating oil) in the exhaust gas flowing from the inflow side flow path are formed. Sulfate (composite composed of sulfuric acid mist, etc.) is collected at the boundary wall and accumulated in the inflow side flow path, and clean exhaust gas with particulates removed is collected in the outflow side flow path. Is discharged through.

On the other hand, when a catalyst is used in the exhaust aftertreatment device 62, the catalyst is supported on the carrier 62A by a known method such as impregnation by immersion, wash coating, ion exchange or the like. Then, while the exhaust gas passes through the small holes 621, the exhaust gas is purified by the action of the catalyst and becomes clean. The catalyst supported on the carrier 62A is
NOx storage reduction catalyst for removing NOx (nitrogen oxide), NOx storage catalyst, oxidation catalyst for oxidizing and removing HC and CO (carbon monoxide), hydrocarbons, carbon monoxide, and nitrogen oxides. A three-way catalyst or the like can be used.

The exhaust flow controller 70 is provided to make the amount of exhaust gas recirculation into the combustion chamber 11A by the above-mentioned internal EGR to be an optimum amount, and the exhaust throttle valve 61 of the exhaust throttle valve 61 is operated according to the operating condition of the diesel engine 1. Actuator 6
It controls the operation of 1A. The exhaust flow controller 70 is electrically connected to the engine controller 50 that controls the governor of the fuel injection device and the like in order to detect the operating condition of the diesel engine 1. This allows
The exhaust flow rate controller 70 receives the rotation speed signal indicating the rotation speed of the diesel engine 1 and the fuel supply amount signal indicating the fuel supply amount to the diesel engine 1, which are output from the engine controller 50. There is.

Although not shown, the diesel engine 1 has a rotation speed sensor as a rotation speed detecting means for detecting the rotation speed thereof and a load detecting means for detecting a fuel supply amount to the diesel engine 1. Rack sensors are provided, and each sensor is electrically connected to the engine controller 50. Of these, the rack sensor is
In order to adjust the amount of fuel injected from the fuel injection pump, the position of a rack slidably provided with respect to the plunger is detected.

Further, the exhaust gas purifying device 2 has a temperature sensor 63 for detecting the exhaust temperature at the inlet side of the exhaust post-treatment device 62.
have. The temperature sensor 63 is electrically connected to the exhaust flow controller 70, so that an exhaust temperature signal indicating the exhaust temperature of the diesel engine 1 is input to the exhaust flow controller 70. In addition, the temperature sensor 63 is the carrier 62 of the exhaust aftertreatment device 62.
It may be directly attached to A to detect the temperature of the carrier itself.

The exhaust flow controller 70 as described above is
As shown in FIG. 6, a storage unit 72 serving as a storage unit that stores two types of maps, and a control unit that determines the opening degree of the exhaust throttle valve 61 based on the maps stored in the storage unit 72. And an arithmetic processing unit 71. In addition,
Although not shown, the exhaust flow controller 70 includes an input section to which an output signal from the engine controller 50 and an output signal from the temperature sensor 63 are input, and an exhaust throttle valve, in addition to the arithmetic processing section 71 and the storage section 72. An output unit for outputting an operation signal to the actuator 61A of 61 is provided.

In the storage unit 72, a first map showing the opening degree of the exhaust throttle valve 61 for obtaining the optimum exhaust gas recirculation amount and the optimum exhaust temperature with respect to the engine speed and the fuel supply amount, and the diesel engine 1 With respect to the exhaust gas temperature, the two types of maps are stored: the second map showing the opening degree of the exhaust throttle valve 61 capable of keeping the exhaust gas temperature within a certain temperature range.

In the first map, the optimum exhaust gas recirculation amount is the exhaust gas recirculation amount set in consideration of the NOx reduction rate and the soot generation rate, which change due to the decrease in the maximum combustion temperature. On the other hand, the optimum exhaust gas temperature is an exhaust gas temperature that is set in consideration of the durability of the diesel engine 1 against the exhaust gas temperature rise due to exhaust gas recirculation, the temperature range in which the exhaust aftertreatment device is activated, and the like. In the present embodiment, for example, the exhaust throttle valve 6 that can obtain an optimum exhaust flow rate.
When the value of the opening of 1 is different from the value of the opening of the exhaust throttle valve 61 at which the optimum exhaust temperature is obtained, a substantially intermediate value between them is adopted. It should be noted that the optimum exhaust gas is obtained without adopting a substantially intermediate value between the value of the opening degree of the exhaust throttle valve 61 for obtaining the optimum exhaust flow rate and the value of the opening degree of the exhaust throttle valve 61 for obtaining the optimum exhaust temperature. The value of the opening degree of the exhaust throttle valve 61 that obtains the flow rate may be preferentially adopted, or the value of the opening degree of the exhaust throttle valve 61 that obtains the optimum exhaust temperature may be preferentially adopted.

The second map is a map used when the exhaust gas temperature of the diesel engine 1 is higher than a predetermined temperature range and when it is lower than the predetermined temperature range. When the temperature is higher than the predetermined temperature, it indicates the opening degree of the exhaust throttle valve 61 for decreasing the exhaust temperature, and when the exhaust temperature is lower than the predetermined temperature, it indicates the opening degree of the exhaust throttle valve 61 for increasing the exhaust temperature. . Here, in the second map, when the exhaust gas temperature exceeds the predetermined temperature range, the higher the exhaust gas temperature, the larger the opening of the exhaust throttle valve 61 shown, and the exhaust gas temperature falls below the predetermined temperature range. In this case, the lower the exhaust temperature, the smaller the opening of the exhaust throttle valve 61 shown.

The arithmetic processing unit 71 has an exhaust gas temperature judging unit 71A for judging whether or not the inputted exhaust gas temperature signal is within a predetermined temperature range set in advance, and the operating state of the diesel engine 1 is in a rapid acceleration state. It is configured to include an operating state determination unit 71B that determines whether or not there is an exhaust gas flow rate control unit 71C that determines the opening degree of the exhaust throttle valve 61.

In the exhaust gas temperature determination unit 71A, the predetermined temperature range is set to a range corresponding to the temperature range in which the exhaust post-treatment device 62 is activated (hereinafter, activation temperature range).
In such an exhaust temperature determination unit 71A, the exhaust temperature of the diesel engine 1 is "higher than the active temperature range",
It is determined whether it is “in the active temperature range” or “lower than the active temperature range”. Further, the exhaust temperature determination unit 71A outputs the determination result to the exhaust flow rate control unit 71C.

The operating state determination unit 71B calculates the fluctuation rate (dN / dt) of the engine rotation speed in the diesel engine 1 based on the input engine rotation speed signal, and the engine rotation speed fluctuation rate and the preset value. It is designed to be compared with the reference value set. This reference value is set to a value corresponding to the engine rotation speed fluctuation rate when the operating state of the diesel engine 1 is in the rapid acceleration state. Further, the operating state determination unit 71B outputs the comparison result to the exhaust flow rate control unit 71C.

The exhaust flow rate control unit 71C controls the operation of the actuator 61A based on the first map and the second map stored in the storage unit 72, and appropriately adjusts the opening degree of the exhaust throttle valve 61. It is a part. The exhaust flow rate control unit 71C determines which of the first map and the second map to use based on the input signal from the exhaust temperature determination unit 71A, and based on the selected map. , And outputs an operation signal to the actuator 61A.

Next, the operation of this embodiment will be described. First, when a starting switch (not shown) of the diesel engine 1 is turned on, the crankshaft starts to be rotated by a drive source such as a starting device, the diesel engine 1 is started, and an output signal from the starting switch is output to the engine controller. 50 and the exhaust flow rate controller 70, and each controller 5
0 and 70 are activated. 7, in step S11, the engine rotation speed signal and the fuel supply amount signal from the engine controller 50 are the exhaust flow rate controller 70.
Is input to step S12.

In step S12, the operating state determination unit 71B of the exhaust flow controller 70 calculates the engine rotation speed fluctuation rate dN / dt from the input engine rotation speed signal, and the calculated engine rotation speed fluctuation rate dN / d.
By comparing t with a preset reference value, the diesel engine 1 has a small fluctuation rate dN / dt, a steady state in which the engine rotation speed is substantially stable (including an acceleration state), and a fluctuation rate dN / dt. Is large and the engine speed is greatly increasing, and check whether it is in the rapid acceleration state. Then, when the diesel engine 1 is in the rapid acceleration state, the process proceeds to step S13, and when the diesel engine 1 is in the steady state, the process proceeds to step S14.

In step S13, since the diesel engine 1 is in a rapid acceleration state and the turbo lag of the supercharger 41 is insufficient to supply the intake air to the combustion chamber 11A, the intake air is introduced into the combustion chamber 11A. In order to make it easy, the opening degree of the exhaust throttle valve 61 is made almost fully open, and step S1
Return to 1. As a result, the exhaust pressure with respect to the intake pressure is reduced, so that intake air easily enters the combustion chamber 11A, and a large amount of intake air is supplied into the combustion chamber 11A. Therefore, it becomes possible to secure the output required for the rapid acceleration, and the deterioration of the rapid acceleration performance of the diesel engine 1 is prevented. When the operating state determination unit 71B of the exhaust flow controller 70 determines that the diesel engine is in the rapid acceleration state, the exhaust flow control unit 71C selects both the first and second maps of the storage unit 72. Instead, an operation signal for fully opening the exhaust throttle valve 61 is output to the actuator 61A of the exhaust throttle valve 61.

In step S14, the exhaust temperature of the diesel engine 1 is input, and the process proceeds to step S15. In step S15, the input exhaust temperature T reaches the predetermined temperature T1 by the exhaust temperature determination unit 71A of the exhaust flow controller 70. It is confirmed whether or not it is, and if it is reached, the process proceeds to step S16, and if it is not reached, the step S1 is performed.
Proceed to 7. Here, the predetermined temperature T1 is set to an upper limit temperature of a temperature range in which the exhaust post-treatment device 62 is activated (hereinafter referred to as an activation temperature range). It should be noted that the diesel engine 1 is higher than the upper limit temperature of the activation temperature range of the exhaust aftertreatment device 62.
When the permissible temperature due to the durability is lower, the predetermined temperature T1 is set to the permissible temperature of the diesel engine 1.

In step S15, if the exhaust gas temperature T has reached the predetermined temperature T1, the exhaust gas temperature T is too high and the temperature of the exhaust gas post-treatment device 62 exceeds the upper limit of the active temperature range. In order to keep the temperature of the device 62 within the active temperature range, the exhaust flow rate controller 70 includes the storage unit 7
The opening degree of the exhaust throttle valve 61 is adjusted based on the second map No. 2 and the process returns to step S11. Specifically, the exhaust temperature is reduced by increasing the opening of the exhaust throttle valve 61 to reduce the exhaust pressure with respect to the intake pressure and reducing the exhaust gas recirculation amount. As a result, the temperature of the exhaust after-treatment device 62 also falls and falls within the activation temperature range, and the exhaust gas purification efficiency becomes good. Here, in the second map, when the exhaust temperature T exceeds the predetermined temperature T1, the higher the exhaust temperature T, the larger the opening of the exhaust throttle valve 61 shown. Thus, when the exhaust gas temperature T is considerably high, the exhaust gas temperature T is greatly reduced by considerably increasing the opening degree of the exhaust throttle valve 61, and the exhaust gas temperature T can be quickly lowered to the active temperature range. On the other hand, when the exhaust gas temperature T is a little high, the exhaust gas temperature T is decreased a little by increasing the opening degree of the exhaust gas throttle valve 61, and it is prevented that the exhaust gas temperature T is excessively decreased and falls below the active temperature range. .

In step S17, the exhaust temperature determination unit 71A of the exhaust flow controller 70 confirms whether the exhaust temperature T has reached the predetermined temperature T2. If not, the process proceeds to step S18, and if it has reached it. Advances to step S19. Here, the predetermined temperature T2 is set to the lower limit temperature of the activation temperature range of the exhaust aftertreatment device 62.

In step S18, if the exhaust temperature T does not reach the predetermined temperature T2, the exhaust temperature T is too low and the temperature of the exhaust post-treatment device 62 falls below the lower limit of the active temperature range. In order to keep the temperature of the device 62 within the activation temperature range, the exhaust flow rate controller 70 adjusts the opening degree of the exhaust throttle valve based on the second map of the storage unit 72, and returns to step S11. Specifically, the exhaust temperature is raised by decreasing the opening of the exhaust throttle valve 61 to raise the exhaust pressure with respect to the intake pressure and increasing the exhaust gas recirculation amount. As a result, the temperature of the exhaust aftertreatment device 62 also rises and falls within the activation temperature range, and the exhaust gas purification efficiency becomes good. Here, in the second map, when the exhaust temperature T has not reached the predetermined temperature T2, the lower the exhaust temperature T, the smaller the opening of the exhaust throttle valve 61 shown. Thus, when the exhaust gas temperature T is considerably low, the exhaust gas temperature T is greatly increased by considerably reducing the opening degree of the exhaust throttle valve 61, and the exhaust gas temperature T can be quickly raised to the active temperature range. On the other hand, when the exhaust gas temperature T is slightly low, the exhaust gas temperature T is slightly increased by slightly reducing the opening degree of the exhaust throttle valve 61, and the exhaust gas temperature T is increased.
Is prevented from rising excessively and exceeding the activation temperature range.

In step S19, the exhaust temperature T is lower than the predetermined temperature T1 and higher than the predetermined temperature T2, that is, the temperature of the exhaust post-treatment device 62 is within the active temperature range. , Storage unit 72
The opening degree of the exhaust throttle valve 61 is adjusted based on the first map of No. 1, and the process returns to step S11. As a result, in the diesel engine 1, the optimal exhaust gas recirculation amount is obtained and NOx
The reduction efficiency becomes good, and the temperature of the exhaust post-treatment device 62 is within the activation temperature range, so that the exhaust gas purification efficiency in the exhaust post-treatment device 62 also becomes good. Then, after returning from each step to step S11, a series of steps starting from step S11 is repeated until the diesel engine 1 is stopped.

According to the first embodiment as described above, the following effects can be obtained. In the present embodiment, during the intake stroke of the diesel engine 1, the exhaust valve 14 causes the combustion chamber 11A to move.
The inside is communicated with the exhaust passage 30, and the exhaust throttle valve 6
Since the amount of exhaust gas flowing through the exhaust passage 30 is adjusted by 1, the combustion chamber 1 does not change even if the pressure difference between the exhaust side and the intake side fluctuates.
It is possible to control the amount of exhaust gas that is recirculated into 1A. The optimum exhaust gas recirculation amount is set for the operating condition of the diesel engine 1, and the opening of the exhaust throttle valve 61 is adjusted so that the set exhaust gas recirculation amount is obtained. Even if it is higher, the exhaust pressure can be increased with respect to the intake pressure, and the set amount of exhaust gas can be recirculated into the combustion chamber 11A. As a result, the optimum amount of exhaust gas can always be returned to the inside of the combustion chamber 11A, so that the NOx reduction efficiency by the internal EGR can be improved.

The exhaust gas purifying device 2 is replaced by the exhaust aftertreatment device 6
Since the exhaust gas purifying apparatus 2 is configured to include NO 2, NOx in the exhaust gas can be reduced by the internal EGR, and the exhaust post-treatment device 62 can purify the exhaust gas, so that the exhaust gas is further cleaned. be able to. Further, by appropriately adjusting the amount of exhaust gas flowing through the exhaust passage 30 by the exhaust throttle valve 61 to control the exhaust pressure and exhaust gas recirculation amount that affect the exhaust temperature, the exhaust temperature is raised or lowered, Exhaust temperature aftertreatment device 62
Since it is within the activation temperature range of, the exhaust gas purification efficiency can be improved.

As an exhaust flow rate adjusting means, an exhaust throttle valve 61
Therefore, the exhaust flow rate adjusting means can be installed at any position without being restricted by the design and structure of the diesel engine 1. Thereby, the installation position of the actuator 61A for opening and closing the valve of the exhaust throttle valve 61 can be arbitrarily set,
If the exhaust throttle valve 61 and the actuator 61A are installed in the empty space of the diesel engine 1, the degree of freedom in designing the diesel engine 1 can be maintained.

In the exhaust flow controller 70, the storage unit 7
Since the opening degree of the exhaust throttle valve 61 is adjusted based on the first map and the second map stored in No. 2, the opening degree of the exhaust throttle valve 61 is adjusted according to the operating condition of the diesel engine 1. Can be done quickly.

In the exhaust gas flow controller 70, when the exhaust gas temperature is higher than the active temperature range of the exhaust post-treatment device 62, the opening degree of the exhaust throttle valve 61 is increased to lower the exhaust gas temperature so that the exhaust gas temperature is lower than the active temperature range. When the exhaust gas is low, the exhaust throttle valve 61 is decreased in opening degree to raise the exhaust gas temperature, so that the exhaust gas temperature can always be kept within the active temperature range. Good efficiency can be maintained.

In the second map stored in the storage section 72 of the exhaust flow controller 70, when the exhaust temperature T exceeds the predetermined temperature T1 (active temperature range), the exhaust temperature T
Is higher, the opening degree of the exhaust throttle valve 61 is larger. Therefore, when the exhaust gas temperature T is considerably high, the exhaust gas temperature T is greatly reduced, and the exhaust gas temperature T is rapidly lowered to the active temperature range. You can On the other hand, exhaust temperature T
When is slightly higher, the exhaust temperature T can be reduced to a small extent to prevent the exhaust temperature T from excessively decreasing and falling below the active temperature range.

In the second map stored in the storage unit 72 of the exhaust flow controller 70, when the exhaust temperature T does not reach the predetermined temperature T2 (active temperature range), the lower the exhaust temperature T is, the lower the exhaust gas shown is. Since the opening degree of the throttle valve 61 is small, the exhaust temperature T can be greatly increased when the exhaust temperature T is considerably low, and the exhaust temperature T can be quickly raised to the active temperature range. On the other hand, when the exhaust gas temperature T is a little low, the exhaust gas temperature T is slightly increased,
It is possible to prevent the exhaust temperature T from rising excessively and exceeding the active temperature range.

In the exhaust flow controller 70, when the operating condition of the diesel engine 1 is in the rapid acceleration state, the opening degree of the exhaust throttle valve 61 is substantially fully opened. It is easy for intake air to enter the inside of 11A, so that a large amount of intake air can be supplied to the diesel engine 1. Therefore, the engine output required for the sudden acceleration can be secured, and even if the exhaust gas purification device 2 is provided in the diesel engine 1, it is possible to avoid impairing the rapid acceleration performance of the diesel engine 1.

At the intake / exhaust timing of the diesel engine 1, the intake valve 13 and the exhaust valve 14 are opened and closed at the timings shown in FIG. 4, so that the crankshaft angle does not reach the bottom dead center, that is, When the negative pressure in the combustion chamber 11A is large, the intake valve 13 can be closed to increase the resistance on the intake side, and the exhaust valve 14 shown in the curve C2 can be lifted to reduce the resistance on the exhaust side. Exhaust gas recirculation can be supplied into the combustion chamber 11A. As a result, the maximum amount of exhaust gas that can be returned to the combustion chamber 11A can be increased, so the exhaust throttle valve 61
It is possible to increase the upper limit value of the exhaust gas recirculation amount that can be controlled by adjusting the opening degree.

[Second Embodiment] FIG. 8 shows a second embodiment of the present invention.
A system according to an embodiment is shown. In the second embodiment, the exhaust throttle valve 61 is adopted as the exhaust flow rate adjusting means in the first embodiment, and the exhaust throttle valve 61 is used.
The amount of exhaust flowing through the exhaust passage 30 was adjusted by
Instead of the exhaust throttle valve 61, an exhaust turbine 64B of a variable turbocharger 64 is adopted as an exhaust flow rate adjusting means, and the exhaust gas flowing through the exhaust passage 30 is adjusted by the exhaust turbine 64B.

That is, in FIG. 8, the diesel engine 1 has a supercharger 41, which is different from the first embodiment.
Instead of the above, a variable turbocharger 64 is provided.
The variable turbocharger 64 has a compressor 64A arranged in the intake passage 20 and an exhaust turbine 64B arranged in the exhaust passage 30. In the variable turbocharger 64, the exhaust turbine 64B is rotated by utilizing the exhaust gas, whereby the compressor 64A is rotationally driven to compress the intake air, and thereby the diesel engine 1 is supercharged.

Here, although not shown, the exhaust turbine 64B of the variable turbocharger 64 is provided with a plurality of movable vanes in the nozzle portion, and the inclination of these vanes is changed to change the inclination of the nozzles. The area, that is, the turbine inlet area is variable. The tilt of these vanes is changed by an actuator 64C composed of a cylinder, a motor, etc., and the operation of the actuator 64C is
It is controlled by the exhaust flow controller 70.

In the variable turbocharger 64 having such a structure, when the nozzle area is narrowed, the flow velocity of exhaust gas increases, the rotation speed of the exhaust turbine 64B increases, and the supercharging pressure increases, so that when internal EGR is performed. (Exhaust valve 1 shown by curve C2
The exhaust gas recirculation amount in the case of the lift 4) is reduced. If the nozzle area is further narrowed and the opening is reduced further than this, the flow rate of the exhaust gas flowing through the exhaust passage 30 is narrowed, and the rotation speed of the exhaust turbine 64B is reduced.
As the exhaust pressure on the upstream side of 4B increases and the intake pressure (supply pressure) on the downstream side of the compressor 64A decreases,
The exhaust gas recirculation amount at the time of internal EGR increases. On the other hand, when the throttle of the nozzle area is released, the intake pressure (supply pressure) on the downstream side of the compressor 64A increases,
The exhaust gas recirculation amount at the time of internal EGR is reduced.

Therefore, when the exhaust temperature of the diesel engine 1 is raised, it is sufficient to raise the exhaust pressure and increase the exhaust gas recirculation amount.
0 outputs an operation signal to the actuator 64C of the variable turbocharger 64 to operate the vane to greatly reduce the turbine inlet area. On the other hand, when lowering the exhaust temperature of the diesel engine 1, it is sufficient to lower the exhaust pressure and reduce the exhaust gas recirculation amount. Therefore, the exhaust flow controller 70 causes the vane 64 to the actuator 64C of the variable turbocharger 64. Is operated to output an operation signal indicating that the turbine inlet area is slightly reduced or that the turbine inlet area is substantially fully opened.

In the exhaust flow rate controller 70 of the second embodiment, in the exhaust flow rate controller 70 of the first embodiment described above, the first map and the second map stored in the storage unit 72 are the exhaust throttle valve. The first map and the second map indicate that the exhaust flow rate control unit 71C outputs an operation signal to the actuator 61A of the exhaust throttle valve 61 while indicating the opening degree of the turbine of the variable turbocharger 64. In addition to indicating the opening of the inlet area, the exhaust flow rate control unit 71C outputs an operation signal to the actuator 64C of the variable turbocharger 64. Other configurations are the same as those of the first embodiment. Since it is the same as the exhaust flow rate controller 70, its explanation is omitted.

According to the second embodiment as described above, the following effects are obtained in addition to the effects of the first embodiment described above. That is, since the exhaust turbine 64B of the variable turbocharger 64 is adopted as the exhaust flow rate adjusting means, the exhaust flow rate through the variable turbocharger 64 is adjusted by appropriately adjusting the inlet area of the exhaust turbine 64B. As a result, the rotation speed of the exhaust turbine 64B can be controlled. Then, the exhaust pressure can be adjusted by adjusting the inlet area of the exhaust turbine 64B.
Since the intake pressure (supply pressure) of the compressor 64A can be adjusted by adjusting the rotation speed of B, the balance between the intake pressure and the exhaust pressure can be adjusted easily and reliably. Therefore, the amount of exhaust gas recirculated into the combustion chamber 11A can be controlled more reliably, and thereby the exhaust gas temperature can be adjusted more reliably.

The present invention is not limited to the above-mentioned embodiment, and modifications and improvements within a range in which the object of the present invention can be achieved are included in the present invention. For example,
The temperature detecting means is not limited to the temperature detecting means for detecting the exhaust temperature near the inlet of the exhaust aftertreatment device, but may be the temperature detecting means for detecting the exhaust temperature on the upstream side of the exhaust passage. However, in such a case, if the exhaust path between the installation position of the temperature detection means and the installation position of the exhaust aftertreatment device is long, there will be a difference between the exhaust temperature detected by the temperature detection means and the temperature of the exhaust aftertreatment device. Therefore, it is preferable to dispose the temperature detecting means as close to the exhaust aftertreatment device as possible.

The exhaust gas purifying device may not have an exhaust after-treatment device. In such a case, the map stored in the storage means indicates the rotational speed of the internal combustion engine and the load of the internal combustion engine. On the other hand, only the map showing the opening degree of the exhaust gas flow rate adjusting means for obtaining the optimum exhaust gas recirculation amount is provided.

The internal combustion engine is not limited to the spontaneous ignition diesel engine, but may be a spark ignition gasoline engine or a non-supercharged engine.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a diesel engine and an exhaust gas purification device according to a first embodiment of the present invention.

FIG. 2 is a graph illustrating an intake / exhaust timing of the diesel engine in the first embodiment.

FIG. 3 is a graph illustrating another intake / exhaust timing of the diesel engine in the first embodiment.

FIG. 4 is a graph illustrating still another intake / exhaust timing of the diesel engine in the first embodiment.

FIG. 5 is a perspective view showing an exhaust aftertreatment device in the first embodiment.

FIG. 6 is a block diagram showing an exhaust flow controller in the first embodiment.

FIG. 7 is a flowchart for explaining an operation in the first embodiment.

FIG. 8 is a schematic configuration diagram showing a diesel engine and an exhaust gas purification device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diesel engine which is an internal combustion engine, 2 ... Exhaust gas purification device, 11A ... Combustion chamber, 13 ... Intake valve, 14 ... Exhaust valve which is exhaust passage opening / closing means, 20 ... Intake passage, 30 ... Exhaust passage, 61 ... Exhaust Exhaust throttle valve that is a flow rate control valve, 62 ... Exhaust aftertreatment device, 63 ... Temperature sensor that is temperature detection means,
64B ... Exhaust turbine which is a turbine, 71 ... Arithmetic processing section which is control means, 72 ... Storage section which is storage means.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01N 3/02 F01N 3/02 321D 3/08 3/08 A 3/24 3/24 BE 3/28 301 3/28 301A 301C F02D 9/04 F02D 9/04 EG 13/02 13/02 K 23/00 23/00 J K P 43/00 301 43/00 301N 301R 301W 301Z F Term (reference) 3G065 AA01 AA03 AA04 AA09 CA12 DA02 DA05 EA04 FA12 GA08 GA10 GA18 KA02 3G084 AA01 BA08 BA19 BA23 BA24 DA04 DA10 FA13 FA27 FA33 3G090 AA03 BA01 DA09 DA12 DA18 3G091 AA10 AA11 AA17 FA17 FA17 FA17 FA17 FA17 FA17 FB17 BA17 BA01 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 BA14 HA14 HA21 HB05 HB06 3G092 AA02 AA11 AA17 AA18 AB03 DA02 DA03 DA12 DB03 DC12 DC15 DF02 DF06 DG07 EA14 EA22 EA25 FA17 FA21 GA08 GA12 HA13X HA15X HB01Z HD01X HD01Z HE01Z

Claims (9)

[Claims] 1. An exhaust gas purification apparatus (2) for an internal combustion engine (1), wherein an intake passage (20) for supplying intake air to the combustion chamber (11A) of the internal combustion engine (1). ), And an exhaust path (3) for exhausting exhaust gas from the combustion chamber (11A).
0) are connected to each other, and an exhaust passage opening / closing means (14) capable of connecting and disconnecting the inside of the combustion chamber (11A) and the exhaust passage (30), and the exhaust passage (rather than the exhaust passage opening / closing means (14). 30)
An exhaust flow rate adjusting means (61, 64B) which is arranged on the downstream side of the exhaust gas and is capable of adjusting the amount of exhaust flowing through the exhaust passage (30) by changing the opening, and the inside of the combustion chamber (11A). During the intake stroke for intake, the combustion chamber (11A) is opened by the exhaust passage opening / closing means (14).
An exhaust gas purifying device (2) for an internal combustion engine (1), characterized in that the inside and the exhaust passage (30) are communicated with each other. 2. The exhaust gas purifying device (2) for an internal combustion engine (1) according to claim 1, wherein an exhaust aftertreatment device (62) for purifying inflowing exhaust gas is provided in the middle of the exhaust passage (30). ) Is installed, the exhaust gas purifying device (2) of the internal combustion engine (1). 3. The exhaust gas purifying apparatus (2) for an internal combustion engine (1) according to claim 1 or 2, wherein the exhaust flow rate adjusting means (61, 64B) changes a valve opening degree. An exhaust gas purification device (2) for an internal combustion engine (1), which is an exhaust flow rate control valve (61) capable of adjusting the amount of exhaust flowing through the exhaust passage (30). 4. The exhaust gas purification apparatus (2) for an internal combustion engine (1) according to any one of claims 1 to 3, wherein the exhaust flow rate adjusting means (61, 64B) is an exhaust turbine (64B). ) To obtain a driving force to supercharge the internal combustion engine (1) and the inlet area of the turbine (64B) is variable, the turbine (64B) of the variable turbocharger (64) An exhaust gas purification device (2) for an internal combustion engine (1), characterized in that 5. An exhaust gas purifying device (2) for an internal combustion engine (1) according to any one of claims 1 to 4, further comprising: a rotational speed detecting means for detecting a rotational speed of the internal combustion engine (1). A load detecting means for detecting a load of the internal combustion engine (1), and an optimum exhaust gas recirculation amount and an optimum exhaust temperature for the rotational speed of the internal combustion engine (1) and the load of the internal combustion engine (1). Based on the map stored in the storage means (72), which stores a map indicating the opening degree of the exhaust gas flow rate control means (61, 64B) for which at least one of An exhaust gas purifying apparatus (2) for an internal combustion engine (1), comprising: a control means (71) for adjusting an exhaust flow rate of the exhaust passage (30) according to an operating state of the engine (1). ). 6. The exhaust gas purification device (2) for an internal combustion engine (1) according to any one of claims 2 to 5, wherein at least the temperature of the exhaust aftertreatment device (62) and the exhaust temperature are included. Temperature detecting means (63) for detecting one
And a control means (71) for controlling the operation of the exhaust flow rate adjusting means (61, 64B), wherein the control means (71) has a temperature detected by the temperature detecting means (63) exceeding a predetermined temperature. If the temperature detected by the temperature detecting means (63) does not reach the predetermined temperature, the exhaust flow rate adjusting means (61, 64B) is opened. 64
An exhaust gas purification device (2) for an internal combustion engine (1), characterized in that the opening of B) is reduced. 7. The exhaust gas purification apparatus (2) for an internal combustion engine (1) according to claim 6, wherein the control means (71) has a temperature detected by the temperature detection means (63) exceeding a predetermined temperature. If the temperature detected by the temperature detecting means (63) is higher, the opening degree of the exhaust flow rate adjusting means (61, 64B) is increased,
When the temperature detected by the temperature detecting means (63) does not reach the predetermined temperature, the lower the temperature detected by the temperature detecting means (63) is, the more the exhaust flow rate adjusting means (61, 64B) is opened. An exhaust gas purification device (2) for an internal combustion engine (1), characterized in that the degree is reduced. 8. An exhaust gas purification apparatus (2) for an internal combustion engine (1) according to any one of claims 1 to 7, wherein when the operating state of the internal combustion engine (1) is a rapid acceleration state, An exhaust gas purifying device (2) for an internal combustion engine (1), characterized in that an opening of an exhaust flow rate adjusting means (61, 64B) is substantially fully opened. 9. The exhaust gas purification apparatus (2) for an internal combustion engine (1) according to any one of claims 1 to 8, wherein the internal combustion engine (1) includes the combustion chamber (11A) and the intake air. Intake valve (13) that can connect and disconnect with the passage (20)
And a crankshaft rotatably driven by combustion / explosion of fuel in the combustion chamber (11A), the intake valve (13) includes the combustion chamber (11A) and the intake passage (20) in the intake stroke. ) And the crank angle at the end of the intake stroke is
The crank angle is set to 150 ° or more and 180 ° or less after the top dead center, and the exhaust passage opening / closing means (14) sets the exhaust passage opening / closing means (14) at any time during the period from the latter half of the intake stroke to immediately after the end of the intake stroke. , Inside the combustion chamber (11A) and the exhaust passage (30)
An exhaust gas purification device (2) for an internal combustion engine (1), characterized in that