WO2010024013A1

WO2010024013A1 - Exhaust gas purifier

Info

Publication number: WO2010024013A1
Application number: PCT/JP2009/060357
Authority: WO
Inventors: 宏司増田; 道彦原
Original assignee: ヤンマー株式会社
Priority date: 2008-08-26
Filing date: 2009-06-05
Publication date: 2010-03-04
Also published as: JP2010053723A

Abstract

Provided is an exhaust gas purifier (1) which can purify exhaust gas uniformly while decreasing the number of components without the need for changing the arrangement of an engine (2). The exhaust gas purifier (1) which purifies exhaust gas of the engine (2) equipped with a hydraulic pump (50) for driving a working machine comprises a particulate filter (10), and a load device (60) for regenerating the particulate filter (10) by removing particulates collected in the particulate filter (10) forcibly, wherein a pressure regulation valve (61) as the load device (60) for regeneration is built in the hydraulic pump (50) for driving a working machine and provided integrally.

Description

Exhaust purification device

The present invention relates to an exhaust emission control device for purifying exhaust gas in an internal combustion engine such as a diesel engine.

Conventionally, as a technique for collecting particulates contained in exhaust gas discharged from an engine, it is known to equip an engine exhaust purification device having a particulate filter in the middle of the exhaust passage of the engine. The particulate filter has a porous honeycomb structure made of ceramic or the like, the inlets of the respective flow paths partitioned in a lattice shape are alternately sealed, and the flow paths in which the inlets are not sealed are as follows: Only the exhaust gas which permeate | transmits the porous wall which divides each flow path, and is comprised so that the exit may be sealed is discharged | emitted downstream.

When exhaust gas permeates through the porous wall, the particulates in the exhaust gas are purified by being collected inside the porous wall, but the particulates are accumulated inside the porous wall. For this reason, an increase in exhaust resistance and an increase in the differential pressure between the inlet side and the outlet side of the particulates occur, affecting the performance of the engine. Therefore, a technique for burning and removing particulates before the particulate filter reaches such a state is known.
However, when the engine load is small and the temperature of the exhaust gas is low, there is a problem that the particulates are not burned off.

Therefore, a technique for removing the particulates accumulated on the particulate filter to recover the particulate collection ability of the particulate filter, in other words, a technique for regenerating the particulate filter is known. For example, a technique is known in which an electrothermal heater is provided upstream of the filter with an oxidation catalyst in the exhaust path of the engine, and the exhaust gas temperature led to the filter with the oxidation catalyst is increased by heating the heater (Patent Document). 1).
JP 2001-280121 A

However, in the conventional configuration, since a dedicated heater for exhaust gas silencing is required, the number of parts is increased, and the arrangement of the engine must be changed to take up space, which contributes to an increase in cost. There was a problem. Also. The exhaust gas must be heated locally by the heater, and the exhaust gas cannot be uniformly heated, so that the exhaust gas cannot be purified uniformly.

In view of the above problems, the present invention provides an exhaust emission control device that eliminates the number of parts, does not need to change the arrangement of the engine, and can purify exhaust gas uniformly.

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, according to claim 1, in the exhaust emission control device comprising a particulate filter, forcibly removing particulates accumulated in the particulate filter, and comprising a regeneration load device for regenerating the particulate filter, The regeneration load device is constituted by a pressure adjustment valve of a hydraulic load mechanism, and the pressure adjustment valve is switched and driven between a normal state where no pressure rises and a high pressure state where the pressure is increased by a predetermined pressure. The pressure adjustment valve is provided on the discharge side of the hydraulic load mechanism, and the pressure adjustment valve is provided adjacent to the hydraulic load mechanism.

According to a second aspect of the present invention, the hydraulic load mechanism is configured by a hydraulic pump for a work machine that drives the work machine, and the pressure adjusting valve is provided integrally with the hydraulic pump for the work machine.

According to a third aspect of the present invention, the hydraulic load mechanism is configured by a hydraulic pump for a work machine that drives the work machine, and the pressure adjustment valve is disposed on a hydraulic outlet side of the hydraulic pump for the work machine and the hydraulic pump for the work machine. It is provided separately.

According to a fourth aspect of the present invention, the hydraulic load mechanism includes a regeneration hydraulic pump that is provided separately from a work implement hydraulic pump that drives the work implement, and the regeneration load device includes a pressure of the regeneration hydraulic pump. It consists of a regulating valve and a pressure control valve.

In claim 5, the regeneration load device is disposed in a gear case provided on a side surface of the engine.

As the effects of the present invention, the following effects are obtained.

In claim 1, exhaust gas can be purified uniformly. In addition, space can be saved and a compact configuration can be achieved.

In claim 2, the exhaust gas can be purified uniformly. Further, by integrating the regenerative load device into the working machine hydraulic pump, space can be saved, and a compact configuration can be achieved.

According to the third aspect of the present invention, since the regeneration load device is provided separately, it can be removed when the regeneration load device is not required, and the structure of the other hydraulic pumps for work machines is made common. be able to.

According to the fourth aspect of the present invention, an engine that does not have a work machine hydraulic pump can be loaded by the regeneration load unit.

In claim 5, an engine that does not have a work machine hydraulic pump can be loaded by the regeneration load unit. Further, by disposing in the gear case, it is possible to apply a load without affecting the arrangement of other PTOs.

The functional block diagram which showed the whole structure of the engine which concerns on one Embodiment of this invention, and an exhaust gas purification apparatus. Sectional drawing which showed the hydraulic pump for working machines, and the hydraulic control valve. The hydraulic circuit diagram which showed the hydraulic pump for working machines, and the hydraulic control valve. The functional block diagram which showed the whole structure of the engine and exhaust emission control apparatus concerning another embodiment. Sectional drawing which showed the hydraulic pump for working machines and hydraulic control valve concerning another embodiment. The hydraulic circuit diagram which showed the hydraulic pump for working machines and hydraulic control valve concerning another embodiment. The functional block diagram which showed the whole structure of the engine which concerns on another embodiment, and an exhaust gas purification apparatus. Sectional drawing which showed the load unit for reproduction | regeneration. The hydraulic circuit diagram which showed the load unit for reproduction | regeneration. The functional block diagram which showed the whole structure of the engine which concerns on another embodiment, and an exhaust gas purification apparatus. Explanatory drawing which shows the relationship between an engine load and an engine speed. The flowchart figure of filter reproduction | regeneration control.

Next, embodiments of the invention will be described.
FIG. 1 is a functional block diagram showing the overall configuration of an engine and an exhaust emission control device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a hydraulic pump for a working machine and a hydraulic control valve, and FIG. FIG. 4 is a functional block diagram showing an overall configuration of an engine and an exhaust emission control device according to another embodiment, and FIG. 5 is a working machine according to another embodiment. FIG. 6 is a hydraulic circuit diagram showing a working machine hydraulic pump and a hydraulic control valve according to another embodiment, and FIG. 7 is an engine and an exhaust purification device according to another embodiment. FIG. 8 is a sectional view showing the regeneration load unit, FIG. 9 is a hydraulic circuit diagram showing the regeneration load unit, and FIG. 10 is an engine and exhaust according to another embodiment. Overall structure of the purification device Functional block diagram showing, 11 is an explanatory diagram showing a relationship between the engine load and engine speed, Figure 12 is a flow chart of a filter regeneration control.

Hereinafter, an exhaust emission control device 1 which is an embodiment of an exhaust emission control device for an engine according to the present invention will be described with reference to FIG.

[Configuration of exhaust purification system]
As shown in FIG. 1, an engine exhaust purification device 1 is provided in an engine 2 that is an embodiment of an engine in the present invention. The exhaust purification device 1 purifies exhaust gas generated by the engine 2 and discharges it.
The engine exhaust purification device 1 includes a particulate filter 10, a detection means 20, a controller 21, a notification means 40, and the like.

The particulate filter 10 is disposed in the exhaust path 2b of the engine 2 and removes particulates (e.g., carbonaceous soot, high boiling point hydrocarbon component (SOF)) in the exhaust gas. Specifically, the particulate filter 10 has a honeycomb structure composed of a porous wall of ceramic or the like, and the exhaust gas is configured to be discharged after passing through the porous wall. When the exhaust gas passes through the porous wall, particulates in the exhaust gas are collected on the porous wall. As a result, the particulates are removed from the exhaust gas.

Detecting means 20 detects exhaust pressure, exhaust temperature, etc. upstream and downstream of the particulate filter 10. Specifically, the detection means 20 includes a pressure sensor 20a disposed on the outlet side of the particulate filter 10, a temperature sensor 20b for detecting the exhaust gas temperature of the particulate filter 10, and an engine rotation sensor 20d for detecting the engine speed. The rack position sensor 20e for detecting the fuel injection amount is connected to the controller 21.

The controller 21 is connected to the detection means 20, the notification means 40, a regeneration load device 60, which will be described later, an engine control unit, and the like. The controller 21 mainly includes a storage unit 22, a calculation unit, and the like. The storage unit 22 includes a ROM that stores various control programs and a RAM that is used as a work area for data storage and program execution.
The controller 21 calculates the clogged state of the particulate filter 10 from the pressure of the particulate filter 10 detected by the detecting means 20 and determines whether it is necessary to remove the particulates accumulated on the particulate filter 10.

The

fuel injection valves

32, 32,... Are constituted by electromagnetic valves or the like, and directly inject fuel into a plurality of cylinders configured in the engine 2. By changing the timing of fuel injection into the cylinder, it is possible to change the rotational speed, torque, etc., and also to change the exhaust temperature and supply unburned fuel to the exhaust gas.

The intake throttle valve 33 is provided with a valve body that is opened and closed by an electromagnetic valve or an actuator, and is disposed in the intake path 2a of the engine 2 to adjust the air inflow amount of the engine 2. By changing the opening of the intake throttle valve 33, it is possible to change the exhaust gas flow rate, the exhaust temperature, and the exhaust speed.

The notifying means 40 is a means for notifying whether or not the particulate filter 10 is being played back, and notifies before starting the playback or notifies the playback method. The notification unit 40 includes a visual notification unit 42 such as a monitor or an auditory notification unit 43 such as a speaker, and is connected to the controller 21.

The engine 2 is provided with a working machine hydraulic pump 50 that is driven by the rotational power of the output shaft of the engine 2 as an example of a hydraulic load mechanism. The work machine hydraulic pump 50 supplies hydraulic oil to a work machine hydraulic circuit 52 in a hydraulic device such as a hydraulic lifting mechanism.

As shown in FIGS. 2 and 3, the suction side of the working machine hydraulic pump 50 is connected to a hydraulic oil tank 51, and the discharge side of the working machine hydraulic pump 50 is a regeneration load device 60 described later. To the working machine hydraulic circuit 52.

The regeneration load device 60 includes a pressure regulating valve 61. The pressure regulating valve 61 keeps the pressure and flow rate on the working machine hydraulic circuit 52 side constant, and the working machine hydraulic pump 50 side. Is switched between a normal state in which there is no pressure increase on the working machine hydraulic pump 50 side and a high pressure state in which the pressure on the working machine hydraulic pump 50 side is increased by a predetermined pressure. It is configured.

When the pressure regulating valve 61 is switched to a high pressure state in which the pressure on the working machine hydraulic pump 50 side is increased by a predetermined pressure, the discharge pressure of the working machine hydraulic pump 50 increases and the engine load increases accordingly. That is, by adjusting the pressure of the pressure adjusting valve 61, the discharge pressure of the working machine hydraulic pump 50 can be increased to increase the engine load and execute the filter regeneration control.
[Embodiment 1]

Next, the arrangement of the pressure regulating valve 61 which is the regeneration load device 60 will be described.
As shown in FIG. 1, the pressure regulating valve 61 is incorporated in the working machine hydraulic pump 50 and is configured integrally with the working machine hydraulic pump 50. By forming in this way, a space can be saved and a compact configuration can be achieved.

As shown in FIGS. 2 and 3, a pressure adjusting valve 61 is provided in a hydraulic pump case 50 a of the working machine hydraulic pump 50. The pressure adjusting valve 61 includes an electromagnetic solenoid 65, a spring 66, a spool 67, and the like. By switching the electromagnetic solenoid 65, it is possible to change to a normal state or a high pressure state.
[Embodiment 2]

Further, as shown in FIG. 4, the regeneration load device 60 may be provided separately on the hydraulic outlet 50b side of the working machine hydraulic pump 50. With this configuration, when the regeneration load device 60 is not required, it can be removed, and the structure of the other working machine hydraulic pump 50 can be made common.

As shown in FIGS. 5 and 6, a pressure regulating valve case 61a is detachably provided on the hydraulic outlet 50b side of the working machine hydraulic pump 50, and the pressure regulating valve case 61a has the pressure regulating valve 61a inside. 61 is provided. Since the configuration of the pressure regulating valve 61 is the same as that of the first embodiment, the description thereof is omitted.
[Embodiment 3]

Further, as shown in FIG. 7, the regeneration load device 60 can be constituted by a regeneration load unit 71. With this configuration, the regeneration load unit 71 can also apply a load to the engine 2 that does not have the work machine hydraulic pump 50.

As shown in FIGS. 8 and 9, the regeneration load unit 71 includes a regeneration hydraulic pump 72, a pressure adjustment valve 73, a throttle valve 74 as a pressure control valve, and the like, in addition to the work machine hydraulic pump 50. Yes. The pressure adjusting valve 73 is composed of an electromagnetic solenoid 75, a spring 76, a spool 77 and the like, and can be changed to a normal state or a high pressure state by switching the electromagnetic solenoid 75. By moving the pressure regulating valve 73 and the throttle valve 74, it is possible to completely shut off the pressure oil.
[Embodiment 4]

Further, as shown in FIG. 10, the regeneration load device 60 may be constituted by a regeneration load unit 71 and provided in a gear case 2c for transmitting the power of the engine 2 to the working machine. The gear case 2 c is provided on the side surface of the engine 2. With this configuration, the regeneration load unit 71 can also apply a load to the engine 2 that does not have the work machine hydraulic pump 50. Further, by arranging the reproducing load unit 71 in the gear case 2c, it is possible to apply a load without affecting the arrangement of other PTOs.

[Filter regeneration control]
Next, an example of filter regeneration control will be described using FIG. 11 and FIG. It is assumed that the reference load Ls that triggers the operation of the pressure regulating valve 61 is set in advance, for example, by storing it in the storage unit 22 of the controller 21.

The explanatory diagram shown in FIG. 11 is a diagram of a load pattern representing the relationship between the engine speed R and the engine load L when the engine 2 is driven, and is stored in the storage unit 22. In FIG. 11, the engine speed R is plotted on the horizontal axis, and the engine load L correlated with the rack position is plotted on the vertical axis. In this case, the reference load Ls is represented by a horizontal straight line of L = Ls.

The load pattern LP of the present embodiment is a region surrounded by an upwardly convex line, and is vertically changed by a boundary line BL that represents the relationship between the engine speed R and the engine load L when the exhaust gas temperature is a renewable temperature. Divided into The upper area across the boundary line BL is a reproducible area Area1 where particulates deposited on the filter body can be removed, and the lower area is a non-reproducible area Area2 where particles are deposited on the filter body without being removed. It is.

Next, the flow of filter regeneration control using the pressure regulating valve 61 that is the regeneration load device 60 of Embodiment 1 will be described using the flowchart shown in FIG. First, following the start, the reference load Ls stored in the storage unit 22 in advance, the engine load L1 that is the detection value of the rack position sensor 20e, the engine speed R1 that is the detection value of the engine rotation sensor 20d, and the memory The reference pressure value Ps stored in advance in the unit 22 and the detection value P of the pressure sensor 20a are read (step S10), and the engine output is calculated from the magnitude of the pressure difference between the reference pressure value Ps and the detection value P of the pressure sensor 20a. It is determined whether or not particulates are deposited on the particulate filter 10 so as to hinder the operation (step S20).

If the particulate filter 10 has not accumulated particulates, the control is terminated. If particulates are accumulated on the particulate filter 10, the flow resistance in the particulate filter 10 increases and the engine output decreases. Therefore, it is determined whether or not the current engine load L1 is equal to or less than the reference load Ls (step S30).

If the current engine load L1 is equal to or lower than the reference load Ls, it is highly possible that the current engine load L1 is in the non-renewable area Area2, and it can be said that the particulates are accumulated on the particulate filter 10 without being removed. Therefore, the controller 21 excites the electromagnetic solenoid 65 and switches the pressure regulating valve 61 to the high pressure state (step S40).

When the pressure regulating valve 61 is switched to a high pressure state, a regeneration load is applied to the work machine hydraulic pump 50, and the discharge pressure of the work machine hydraulic pump 50 increases. As the discharge pressure of the work implement hydraulic pump 50 increases, the engine load L1 exceeds the boundary line BL and increases by the regeneration load ΔL corresponding to the predetermined pressure, and becomes the engine load L2 (L2 = L1 + ΔL). . At the same time, the engine output increases to maintain the set rotational speed, and the exhaust gas temperature rises.

As a result, when the exhaust gas passes through the particulate filter 10, the exhaust gas temperature exceeds the reproducible temperature, so that the particulates accumulated on the particulate filter 10 are removed, and the particulate filter 10 has a particulate collection ability. Will recover.

After the pressure regulating valve 61 is switched to the high pressure state, the detection value L2 ′ of the rack position sensor 20e and the detection value P ′ of the pressure sensor 20a are read again (step S50), and the engine load L2 ′ is the reference load. It is determined whether or not Ls has been exceeded (step S60).

If the engine load L2 ′ does not exceed the reference load Ls, the process returns to step S50 in order to continue the pressure adjustment by the pressure adjustment valve 61. If the engine load L2 ′ exceeds the reference load Ls, even if there is no regeneration load, for example, it is highly possible that the regeneration area Area1 is reached only by the total load required to drive the power steering mechanism I can say that. Therefore, in order to cancel the increase in the discharge pressure of the working machine hydraulic pump 50 by the pressure adjusting valve 61, the pressure adjusting valve 61 is driven to switch to the normal state (step S70).

By controlling in this way, exhaust pressure is increased as a result of increasing the engine load L by increasing the discharge pressure of the working machine hydraulic pump 50 by adjusting the pressure of the pressure adjusting valve 61 based on the detection information of the pressure sensor 20a. Since the temperature rises, for example, even if the current engine load L1 is in the non-renewable area Area2 and the particulates are not removed but are deposited on the particulate filter 10, the exhaust gas temperature can be regenerated. The particulates can be removed by raising the above, and the particulate collecting ability of the filter body can be reliably recovered regardless of the driving state of the engine 2.

In addition, the pressure adjustment valve 61 that adjusts the discharge pressure of the work machine hydraulic pump 50 operates when the engine load L is equal to or lower than the reference load Ls. For example, the current engine load L1 is in the reproducible area Area1, In a state in which the particulates accumulated on the particulate filter 10 are removed as they are, the pressure regulating valve 61 is maintained in a normal state, and an excessive load is not applied to the engine 2 from the working machine hydraulic pump 50. That is, it is possible to suppress deterioration in fuel consumption associated with filter regeneration control.

Further, when the engine load exceeds the reference load Ls, the pressure adjustment of the pressure adjustment valve 61 is released, so that an excessive load is not applied to the engine 2 due to the load of the working machine hydraulic pump 50. . Therefore, the engine stall due to the regeneration load on the work machine hydraulic pump 50 can be reliably suppressed, and the energy output can be reduced and the engine output can be efficiently used.

As described above, the exhaust gas purification apparatus 1 is an exhaust gas purification apparatus 1 for an engine 2 that includes a work machine hydraulic pump 50 that drives a work machine. The exhaust gas purification apparatus 1 includes a particulate filter 10, and the particulate filter 10. In the exhaust emission control device 1 having the regeneration load device 60 for forcibly regenerating the particulates accumulated in the exhaust gas, the pressure regulating valve 61 that is the regeneration load device 60 is incorporated in the working machine hydraulic pump 50 and integrated. Is provided. With this configuration, exhaust gas can be purified uniformly. Further, by integrating the pressure adjusting valve 61, which is the regeneration load device 60, into the working machine hydraulic pump 50, it is possible to save space and to achieve a compact configuration.

The pressure regulating valve 61 is provided separately on the hydraulic outlet 50b side of the working machine hydraulic pump 50. With this configuration, since the pressure regulating valve 61 is provided separately, the pressure regulating valve 61 can be removed when the pressure regulating valve 61 is not required. Can be common.

Further, in the exhaust gas purification apparatus 1 that includes the particulate filter 10 and includes the regeneration load device 60 that forcibly regenerates the particulates accumulated in the particulate filter 10, the regeneration load device 60 includes the regeneration filter device 60. The regeneration load unit 71 includes a regeneration hydraulic pump 72, a pressure adjustment valve 73, and a throttle valve 74. With this configuration, the regeneration load unit 71 can also apply a load to the engine 2 that does not have the work machine hydraulic pump 50.

Further, the regeneration load unit 71 is disposed in a gear case 2 c provided on the side surface of the engine 2. With this configuration, the regeneration load unit 71 can also apply a load to the engine 2 that does not have the work machine hydraulic pump 50. Further, by disposing in the gear case 2c, it is possible to apply a load without affecting the arrangement of other PTOs.

INDUSTRIAL APPLICABILITY The present invention can be used for an exhaust purification device for purifying exhaust gas in an internal combustion engine such as a diesel engine.

Claims

With a particulate filter,
In an exhaust emission control device comprising a regeneration load device for forcibly removing particulates accumulated in the particulate filter and regenerating the particulate filter,
The regeneration load device is constituted by a pressure regulating valve of a hydraulic load mechanism,
The pressure regulating valve performs regeneration control of the filter by switching and driving between a normal state where there is no pressure increase and a high pressure state where the pressure is increased by a predetermined pressure,
The pressure regulating valve is provided on a discharge side of the hydraulic load mechanism;
The exhaust gas purification apparatus, wherein the pressure regulating valve is provided adjacent to the hydraulic load mechanism.
The hydraulic load mechanism is composed of a working machine hydraulic pump that drives the working machine,
The exhaust gas purification apparatus according to claim 1, wherein the pressure control valve is integrally provided in the working machine hydraulic pump.
The hydraulic load mechanism is composed of a working machine hydraulic pump that drives the working machine,
2. The exhaust emission control device according to claim 1, wherein the pressure regulating valve is provided separately from the work machine hydraulic pump on a hydraulic outlet side of the work machine hydraulic pump.
The hydraulic load mechanism is constituted by a regeneration hydraulic pump provided separately from a working machine hydraulic pump that drives the working machine,
The exhaust purification apparatus according to claim 1, wherein the regeneration load device includes a pressure adjustment valve and a pressure control valve of the regeneration hydraulic pump.
5. The exhaust emission control device according to claim 4, wherein the regeneration load device is disposed in a gear case provided on a side surface portion of the engine.