DE102005052990A1 - Emission control device for an internal-combustion engine which has particle filter for collecting particles of exhaust gas and an inlet air clean up device installed with throttle with facility to monitor emission particles in filter - Google Patents

Abstract

Emission control device for an internal combustion engine (1) with a particle filter (6) for collecting particles from emission gas and an inlet clean up device installed with throttle valve (14). Particles quality is monitored in the particle filter by the instrument range regulation mechanism (2) which also classify operating condition of internal combustion engine.

Description

The The present invention relates to an exhaust gas purification device having a particulate filter for collecting particles in an exhaust gas of a Internal combustion engine.

In the past was the environmental impact of particles or particulate matter (PM) in exhaust gas expelled by a diesel engine an important topic. traditionally, is a diesel particulate filter (DPF) known to be a ceramic porous Medium is that as a countermeasure serves for it. The DPF is used on an exhaust pipe for collecting the particles using a porous one Dividing wall of the DPF arranged. The DPF is burned by regular burning regenerates the collected particles to remove the particles.

A Collection amount of the particles (a PM accumulation amount) is calculated according to a integrated value of an amount of a PM emission on the basis of an operating condition. The PM accumulation amount is based on a differential pressure over calculated the DPF. The regeneration of the DPF is operated when the PM collection amount equal to or greater than a predetermined amount becomes. Then a post-injection is operated to heat the DPF so that a temperature of the DPF so increased will be equal to or greater than a combustion temperature the particle is. However, sometimes the heating means for heating the DPF not necessary because a temperature of the exhaust gas becomes high enough so that the particles spontaneously burn in some operating conditions. Consequently becomes the warming agent preferably according to the operating condition started to effectively regenerate the DPF.

The unaudited Japanese Laid-Open Patent Publication No. 2000-170521 discloses a conventional one DPF regeneration method that selects the heating agent, the corresponds to the operating state of the internal combustion engine when the PM accumulation amount reaches the predetermined amount. The operating conditions (or Load conditions) of the Internal combustion engines are used in a variety of operating areas based on an engine speed and an output torque classified. Then a regeneration operation is operated, the corresponds to the respective operating area. However, a heating operation becomes not made if the particles are in a certain operating range be burned spontaneously. Thus, the fuel consumption is Regenerating the DPF minimized.

however is used in the method of Japanese Unexamined Patent Publication No. 2000-170521 even if the PM accumulation amount is larger than the predetermined amount is not regeneration, when the operating state is in a low-speed and low-load range located. Likewise, the regeneration is stopped when the operating state the low speed and low load range during regeneration becomes. This is because it is difficult to raise the temperature of the DPF the combustion temperature of the particles in the low-speed and low load range to heat. In other words, a higher one Fuel efficiency preferred. Thus there is a tendency in a case where the operating state in the low-speed and Low load range over a long time remains, such as when idling or while driving in a traffic jam, and regeneration is not undertaken, that the particles are accumulated in the DPF so that they can allowed Amount exceed. The leads to overheating, when the regeneration is done.

on the other hand It is examined that an intake air throttle opening degree decreasing operation additionally made is used to increase the temperature of the DPF. When an opening degree an intake throttle valve that is in an engine intake air passage is decreased, to decrease an intake air amount, If a combustion state of the internal combustion engine is changed, then that a temperature of the exhaust gas increases. Thus, it is possible the DPF through the use of both the intake air throttle opening degree reduction operation as well as another warming agent regenerate together when the operating condition in the low-speed and low load range.

however becomes in a case where the intake air throttle opening degree decreasing operation due to a malfunction of the intake throttle valve is not performed, the effect described above is not achieved. In general the intake throttle valve is open when the valve is not energized is charged. Thus, in this case, in the low-speed and low load range, the temperature of the DPF does not reach an activation temperature an oxidation catalyst increases become. Therefore, the regeneration can not be performed.

In particular, in the low-speed and low-load range of the engine operation, the intake air throttle opening degree decreasing operation may have the same disadvantage as in Japanese Unexamined Patent Publication No. 2000-170521. Thus, the regeneration can not be performed, so that the PM-Ansamm quantity may exceed the permissible quantity. Thus, when the regeneration is performed by the use of another heating means in accordance with a change in the operating range, the temperature of the DPF may excessively increase upon regeneration, so that the DPF may be destroyed or the catalyst may be degraded.

The The present invention is directed to the aforementioned disadvantages directed. Thus, it is an object of the present invention to provide an exhaust gas purification device which restricts that the PM accumulation amount on a particulate filter exceeds the allowable amount.

To the Solve the The object of the present invention is an exhaust gas purification device for an internal combustion engine provided with a particle filter. The particle filter is in one Exhaust passage of the internal combustion engine located to particles of an exhaust gas to accumulate and accumulate the internal combustion engine. The exhaust gas purification device heated the particulate filter through the use of multiple heating devices, having an intake air throttle device that is in an intake air passage the internal combustion engine is located. Likewise, the exhaust gas purification device detects a lot of the particles that are accumulated in the particulate filter, to determine if the amount of particles has a limit to starting achieved a regeneration of the particulate filter. Then classified the exhaust gas purification device an operating state of the internal combustion engine as one of a plurality of predetermined operating areas. Then The exhaust purification device controls the plurality of heating devices based on the amount of particles and operating range. Furthermore, the exhaust gas purification device detects a malfunction of Intake air throttle device and reduces the limit to start the regeneration of the particulate filter in a case where the malfunction the intake air throttle device is detected.

The Invention together with additional tasks, Features and advantages will be best understood from the following description, the appended claims and the associated Drawings understood, wherein:

1 Fig. 10 is a schematic diagram of an exhaust gas purification device for an internal combustion engine according to an embodiment of the present invention;

2 is a graph in which an axis of the engine speed and an axis of the torque show engine operating conditions, which are classified based on a temperature of the exhaust gas;

3 Fig. 10 is a flowchart showing an operation of an ECU according to the present invention;

4 Fig. 10 is a flowchart showing a process of determining a PM accumulation amount;

5 Fig. 10 is a flowchart showing a process for determining an operation area;

6 FIG. 10 is a flowchart showing a process for regeneration control in an engine operating region A in FIG 2 shows;

7 FIG. 13 is a flowchart illustrating the process of regeneration control in an engine operating region B in FIG 2 shows;

8th FIG. 10 is a flowchart illustrating the process for regeneration control in an engine operating region C in FIG 2 shows;

9 FIG. 10 is a flowchart illustrating the process for regeneration control in an engine operating region D in FIG 2 shows; and

10 FIG. 10 is a flowchart illustrating the process for regeneration control in an engine operating region E in FIG 2 shows.

(Embodiment)

An embodiment of the present invention will be described with reference to the accompanying drawings. 1 FIG. 10 is a schematic diagram of an exhaust gas purification device for an internal combustion engine. FIG. The present embodiment is applied to a 4-cylinder diesel engine 1 applied. Every cylinder of the internal combustion engine 1 has an injector 11 in a common rail 3 injected fuel to an internal combustion. The fuel in a fuel tank 4 is through a metering valve 41 transferred. Then the fuel is pumped 31 pumped to the common rail 3 to be fed. A pressure sensor 5 is at the common rail 3 assembled. The pressure sensor 5 detects the pressure of the common rail 3 and gives a signal that measures the pressure of the common rail 3 indicates to an electronic control unit (ECU) 2 from.

A diesel particulate filter (DPF) 6 has one Oxidation catalyst on its surface. The DPF 6 with the oxidation catalyst is in an exhaust passage 12 of the internal combustion engine 1 built-in. The DPF 6 is manufactured by a process for forming heat-resistant ceramic (for example, cordierite ceramic) in a honeycomb structure. At the DPF 6 For example, each of a plurality of cells, which are gas passages, is sealed so that an inlet side and an outlet side of the cell are alternately arranged. Surfaces of walls of the cells are coated with the oxidation catalyst (eg platinum). That of the internal combustion engine 1 discharged exhaust gas flows through porous partitions of the DPF 6 to flow toward the downstream side. The particles are collected between the partitions and are gradually accumulated. In the present embodiment, an oxidation reaction is used to lower a temperature of regeneration, so that the combustion is stabilized. As discussed above, the oxidation catalyst is through the DPF 6 supported. However, the oxidation catalyst may be separately provided to serve as an upstream operation of a DPF process.

temperature sensors 71 and 72 are on an upstream side and a downstream side of the DPF 6 assembled. The temperature sensors 71 and 72 capture temperatures of the exhaust gas passing through the exhaust passage 12 flows. The temperature sensor 71 detects the temperature of the inlet gas to the DPF 6 and outputs a signal indicative of the measured temperature of the intake gas to the ECU 2 from. The temperature sensor 72 detects the temperature of the outlet gas from the DPF 6 and outputs a signal indicative of the measured temperature of the exhaust gas to the ECU 2 from. The temperature sensor 71 serves as a temperature measuring device. The temperature of the inlet gas to the DPF 6 is used to indicate an operating condition of the internal combustion engine 1 to determine. The operating state of the internal combustion engine 1 will be described later. The temperature of the outlet gas from the DPF 6 is used to maintain a temperature of the oxidation catalyst and the DPF 6 capture. It is difficult to control the temperature (a central temperature) of the oxidation catalyst and the DPF 6 to measure directly. Thus, the outlet gas temperature becomes the temperature of the DPF 6 accepted. However, to improve a degree of accuracy of the measurement, the temperature of the DPF 6 taking into account a time delay between the temperature of the DPF 6 and the temperature of the outlet gas can be estimated.

Likewise, a differential pressure sensor 8th with the exhaust gas passage 12 connected to detect the amount of particulates (a PM accumulation amount) collected and by the DPF 6 be accumulated. Druckeinführdurchgänge 81 and 82 are with a respective end of the differential pressure sensor 8th connected. The pressure introduction passage 81 communicates with an upstream side of the DPF 6 , The pressure introduction passage 82 stands with a downstream side of the DPF 6 in connection. The differential pressure sensor 8th gives signals to the ECU 2 according to the differential pressure across the DPF 6 from.

An intake throttle valve 14 serving as an intake air throttle is at an intake air passage 13 of the internal combustion engine 1 located. A construction of the intake throttle valve 14 is well known. The intake throttle valve 14 is opened when energized. An opening degree of the intake throttle valve 14 is according to an instruction of the ECU 2 changed. A passage cross-sectional area of the intake air passage 13 is due to the intake throttle valve 14 changed so that the intake air amount is set. As will be described later, the intake air throttle opening degree decreasing operation is by the use of the intake throttle valve 14 one of a variety of heating means according to the present invention. The heating means performs at least one of post-injection and injection timing delay (or fuel injection timing delay). In other words, the heater performs at least either the post-injection or the injection timing delay.

Various sensors (not shown), such as. An accelerator pedal position sensor, a speed sensor and a fuel level sensor are connected to the ECU 2 connected. The ECU 2 calculates reasonable operating values corresponding to the operating state based on the detected signals from the various sensors. The operating values include a fuel injection amount, a fuel injection timing, and an injection pressure. Then the ECU controls 2 the metering valve 41 to a high-pressure fuel to the common rail 3 to pump, leaving a pressure in the common rail 3 is maintained at a predetermined injection pressure. Then the ECU operates 2 the injectors 11 at a predetermined timing, to fuel injection to the internal combustion engine 1 to control.

Likewise, the ECU controls 2 a regeneration of the DPF 6 such that the ECU 2 the temperature of the DPF 6 increased to a combustion temperature of the particles to burn off and eliminate the accumulated particulates when the PM accumulation amount reaches a predetermined amount. Thus, in the present embodiment, the ECU calculates 2 the PM collection menu ge in the DPF 6 based on a detection result of the differential pressure sensor B. The ECU 2 (PM accumulation amount determining means) determines whether a calculated value of the PM accumulation amount has a reference value (or limit) for starting the regeneration of the DPF 6 reached. The operating state of the internal combustion engine 1 is determined based on a temperature of the exhaust gas and the like. The ECU 2 (Operation Area Determiner) classifies the operation state of the internal combustion engine as one of a plurality of operation areas. Then the ECU controls 2 (the regeneration controller) the heating means to the DPF 6 on the basis of the determination results of the PM accumulation amount determining means and the operation range determining means.

In particular, when the PM accumulation amount reaches the reference value, the ECU selects 2 the most preferred heating means for the service-state internal combustion engine 1 at the time on the basis of the specific operating area. Then the ECU leads 2 a heating operation at the DPF. 2 FIG. 10 shows a relationship between the operating state (an engine speed and a torque in the present embodiment) of the internal combustion engine 1 and the temperature of the exhaust gas. Operating areas with a higher engine speed and higher torque have higher exhaust gas temperatures. Similarly, operating ranges having a lower engine speed and lower torque have low exhaust gas temperatures. In the present embodiment, the operating ranges of the internal combustion engine 1 in 5 categories from a high-speed and high-load range A to a low-speed and low-load range E classified. The temperature of the exhaust gas in the high-speed and high-load region A is high (for example, equal to or greater than 550 ° C). The temperature of the exhaust gas in the low-speed and low-load region E is low (for example, less than 250 ° C). Between regions A and E, a region B (for example, equal to or greater than 500 ° C.), a region C (for example, equal to or greater than 350 ° C.) and a region D (for example, equal to or greater than 250 ° C. C) classified according to the temperature of the exhaust gas.

• (1) In dem Bereich A werden die Partikel, die in dem DPF 6 angesammelt sind, spontan verbrannt, da die Temperatur des Abgases hoch wird (gleich wie oder größer als 550°C). Somit wird die Regeneration des DPF 6 durchgeführt, wenn das Erwärmungsmittel in dem Bereich A nicht betrieben wird.
• (2) In dem Bereich B wird die Einspritzzeitabstimmungsverzögerung durchgeführt, die als das Erwärmungsmittel dient. In diesem Bereich ist die Temperatur des Abgases vergleichsweise hoch (gleich wie oder größer als 500°C). Somit wird die Kraftstoffeinspritzzeitabstimmung verzögert (die Einspritzzeitabstimmungsverzögerung durchgeführt), um die Temperatur des Abgases zu erhöhen, so dass die Temperatur des Abgases höher als üblich wird. Dann wird die Temperatur des DPF 6 möglicherweise erhöht, so dass sie gleich wie oder größer als 550°C wird. Daher werden die Partikel abgebrannt und beseitigt, um den DPF 6 zu regenerieren, und wird begrenzt, dass der Kraftstoffverbrauch ansteigt.
• (3) In dem Bereich C wird die Nacheinspritzung, die als Erwärmungsmittel dient, betrieben, um den DPF 6 zu regenerieren. In diesem Bereich ist die Temperatur des Abgases nicht ausreichend hoch (gleich wie oder größer als 350°C). Somit führt, nachdem der Injektor 11 die Haupteinspritzung durchführt, der Injektor 11 die Nacheinspritzung durch, bei der eine geringe Menge Kraftstoff eingespritzt wird, um Kohlenwasserstoffe in das Abgas zuzuführen, um eine katalytische Verbrennung zu erzeugen. Die Wärme, die durch die Verbrennung der Kohlenwasserstoffe beigebracht wird, erwärmt den DPF 6. Somit wird die Temperatur des DPF 6 gleich wie oder größer als 550°C, um die Partikel abzubrennen. Somit wird der DPF 6 regeneriert. (4) In dem Bereich D dient die Einspritzzeitabstimmungsverzögerung als Erwärmungsmittel, um die Temperatur des Oxidationskatalysators zu erhöhen. Dann wird der DPF 6 durch die Nacheinspritzung regeneriert. In diesem Bereich ist die Temperatur des Abgases bis zu einem gewissen Ausmaß gering (gleich wie oder größer als 250°C). Somit wird der Oxidationskatalysator nicht ausreichend aktiviert. Das kann eine Verschlechterung des Kraftstoffwirkungsgrades bei der Regeneration des DPF 6 zur Folge haben, wenn die Regeneration ausschließlich durch die Nacheinspritzung betrieben wird. Somit wird zuerst die Einspritzzeitabstimmungsverzögerung durchgeführt, um die Temperatur bis auf eine gewisse Temperatur (beispielsweise 350°C) zu erhöhen, so dass der Oxidationskatalysator aktiviert wird. Dann wird die Nacheinspritzung durchgeführt, um die Temperatur des DPF 6 auf gleich wie oder größer als 550°C zu erhöhen, so dass die Regeneration des DPF 6 durchgeführt wird. In ähnlicher Weise ist der Erwärmungsbetrieb in zwei Prozesse geteilt, so dass die zugeführten Kohlenwasserstoffe wirksam verbrannt werden, um die Verschlechterung des Kraftstoffwirkungsgrades zu begrenzen.
• (5) In dem Bereich E dienen die Einspritzzeitabstimmungsverzögerung und der Einlassluftdrosselöffnungsgradverringerungsbetrieb, bei dem der Öffnungsgrad das Einlassdrosselventil 14 verringert wird, um die Einlassluftmenge zu verringern, als Erwärmungsmittel zum Erwärmen des Katalysators. Dann wird die Nacheinspritzung durchgeführt, um den DPF 6 zu regenerieren. In diesem Bereich ist die Temperatur des Abgases niedriger (niedriger als 250°C) als diejenige in dem Bereich D. Somit ist es schwieriger, die Temperatur des Katalysators zu erhöhen. Aus diesem Grund wird die Regeneration des DPF 6 herkömmlicher Weise nicht durchgeführt, da der höhere Kraftstoffwirkungsgrad vorgezogen wird. Jedoch wird in dem vorliegenden Ausführungsbeispiel der Einlassluftdrosselöffnungsgradverringerungsbetrieb, der als Erwärmungsmittel dient, zusätzlich angewandt, um eine Wärmedissipation zu dem Abgas zu begrenzen, ebenso wie die Einspritzzeitabstimmungsverzögerung. Somit kann die Temperatur einfacher erhöht werden. Daher wird die Temperatur des Abgases bis auf gleich wie oder größer als die Aktivierungstemperatur (beispielsweise 350°C) des Oxidationskatalysators erhöht. Dann wird die Nacheinspritzung durchgeführt, um die zugeführten Kohlenwasserstoffe effizient zu verbrennen. Dann wird die Temperatur des DPF 6 erhöht bis auf gleich wie oder größer als 550°C erhöht, so dass die Regeneration des DPF 6 durchgeführt wird.

The heating means and the heating operation according to each area will be described.

• (1) In the area A, the particles that are in the DPF 6 accumulated spontaneously burned as the temperature of the exhaust gas becomes high (equal to or greater than 550 ° C). Thus, the regeneration of the DPF 6 performed when the heating means in the area A is not operated.
• (2) In the area B, the injection timing delay serving as the heating means is performed. In this range, the temperature of the exhaust gas is comparatively high (equal to or greater than 500 ° C). Thus, the fuel injection timing is delayed (the injection timing delay performed) to increase the temperature of the exhaust gas, so that the temperature of the exhaust gas becomes higher than usual. Then the temperature of the DPF 6 possibly increased so that it becomes equal to or greater than 550 ° C. Therefore, the particles are burned off and eliminated to the DPF 6 to regenerate, and it is limited that the fuel consumption increases.
• (3) In the area C, the post-injection serving as the heating means is operated to supply the DPF 6 to regenerate. In this range, the temperature of the exhaust gas is not sufficiently high (equal to or greater than 350 ° C). Thus, after the injector 11 the main injection performs, the injector 11 the post-injection, in which a small amount of fuel is injected to supply hydrocarbons into the exhaust gas to produce catalytic combustion. The heat that is produced by the combustion of the hydrocarbons heats the DPF 6 , Thus, the temperature of the DPF becomes 6 equal to or greater than 550 ° C to burn off the particles. Thus the DPF becomes 6 regenerated. (4) In the region D, the injection timing delay serves as a heating means to raise the temperature of the oxidation catalyst. Then the DPF 6 regenerated by the post-injection. In this range, the temperature of the exhaust gas is, to some extent, low (equal to or greater than 250 ° C). Thus, the oxidation catalyst is not sufficiently activated. This can be a deterioration of the fuel efficiency in the regeneration of the DPF 6 result if the regeneration is operated exclusively by the post-injection. Thus, first, the injection timing delay is performed to raise the temperature to a certain temperature (eg, 350 ° C) so that the oxidation catalyst is activated. Then the post-injection is carried out to the temperature of the DPF 6 to increase to the same as or greater than 550 ° C, allowing the regeneration of the DPF 6 is carried out. Similarly, the heating operation is divided into two processes so that the supplied hydrocarbons are effectively burned to limit the deterioration of the fuel efficiency.
• (5) In the area E, the injection timings are used and the intake air throttle opening degree decreasing operation in which the opening degree is the intake throttle valve 14 is reduced to reduce the intake air amount, as a heating means for heating the catalyst. Then the post-injection is performed to the DPF 6 to regenerate. In this range, the temperature of the exhaust gas is lower (lower than 250 ° C) than that in the region D. Thus, it is more difficult to raise the temperature of the catalyst. For this reason, the regeneration of the DPF 6 conventionally not performed because the higher fuel efficiency is preferred. However, in the present embodiment, the intake air throttle opening degree decreasing operation serving as heating means is additionally applied to limit heat dissipation to the exhaust gas as well as the injection timing retardation. Thus, the temperature can be increased more easily. Therefore, the temperature of the exhaust gas is increased to equal to or greater than the activation temperature (for example, 350 ° C) of the oxidation catalyst. Then, the post-injection is performed to efficiently burn the supplied hydrocarbons. Then the temperature of the DPF 6 increases up to equal to or greater than 550 ° C increases, allowing the regeneration of the DPF 6 is carried out.

The Heating means, which is optionally used in each operating range is in the form of Examples shown. The warming agent is not on the specific details, the representative device and the limited to illustrative examples shown and described. For example, in the present embodiment, the intake air throttle opening degree decreasing operation is performed to to heat the oxidation catalyst in the region E. however In addition, the intake air throttle opening degree reduction operation may be accompanied by another warming agent be used in other areas. Likewise, in the present embodiment the operating divisions divided into 5 categories. However, a number the ranges and the temperature of the exhaust gas (or a limit) each area according to the conditions such as As the types of catalyst and the presence or Absence of the supported Catalyst changed become.

The PM accumulation amount determining means having a characteristic Feature of the present invention will be described.

In the operating area (the area E in 2 ) in which the intake air throttle opening degree decreasing operation is selectively used as the heating means, the regeneration control can not be appropriately operated in a case where the intake air throttle opening degree decreasing operation due to a malfunction of the intake throttle valve 14 not operated. In this situation, it may be difficult to raise the temperature of the catalyst to the E range. Also, if the situation in the region E is maintained for a long time, the particles may be accumulated to exceed the allowable amount. Then, the particles may be burned at one stroke when the regeneration operation is performed due to the operating state change. Then, in the present invention, the PM accumulation amount determining means has a plurality of reference values to determine whether the regeneration of the DPF 6 is needed. In other words, in a normal state, the reference value of the PM accumulation amount is to start the regeneration of the DPF 6 a reference M1. In one case, in the malfunction of the intake throttle valve 14 is detected, the reference value of the PM accumulation amount to start the regeneration of the DPF 6 is changed to a reference value M2 smaller than the reference value M1 (reference value changing means). Therefore, the temperature in the regeneration operation is limited to allowable temperatures of the catalyst and a base material to DPF 6 exceeds. The safety is increased as the reference M1 decreases. However, when the reference value M2 becomes smaller, the regeneration operation is performed more often. Thus, it is preferable to define the highest possible reference M1, which maintains safety. More specifically, a ratio of the reference value M1 in the normal state to the reference value M2 may be 1: 0.8.

When the PM accumulation amount determination means determines that the PM accumulation amount reaches the reference value M2, the operating range is based on 2 classified. Then, the regeneration control means controls the heating means to perform the heating operation corresponding to a respective area around the DPF 6 to regenerate. However, when the operating region determining means classifies the operating state as the region E in which the intake air throttle opening degree decreasing operation is performed, the regeneration is not achieved because the temperature of the catalyst is insufficient due to the malfunction of the intake throttle valve 14 is increased. Thus, the heating operation is performed by the regeneration control means (the regeneration stopping means). In this case, the PM accumulation amount will not immediately reach the limit amount that may cause overheating after the PM accumulation amount reaches the reference value M2. Also, the regeneration operation is directly effected by the regeneration control device the other heating means used is performed when the operating state changes, so that it is classified as another operating region that is different from the region E. Thus, the particles present in the DPF 6 are accumulated, safely burned off.

Control routines through the ECU 2 to regenerate the DPF 6 will be described with reference to flowcharts shown in the 3 to 10 are shown. 3 shows a basic operation of the regeneration of the DPF 6 , This routine is done by the ECU 2 operated at a predetermined time cycle. The step S100 corresponds to the PM accumulation amount determining means (in FIG 4 shown). The step S200 corresponds to the operation area determining means (in FIG 5 shown). Step S300 corresponds to the regeneration control device (in FIGS 6 to 10 shown). In 4 , which shows a PM accumulation amount determination process, becomes a normal state of the intake throttle valve 14 determined at a step S101. When it is determined that the intake throttle valve 14 works normally, the PM accumulation amount in the DPF 6 is compared with the normal reference M1 at step S102. When it is determined that the intake throttle valve 14 does not operate normally, the PM accumulation amount in the DPF becomes 6 with the reference value M2, which is smaller than the reference value M1, compared in step S103.

A malfunction determination of the intake throttle valve 14 at step S101, another routine is performed.

For example, a control signal through the ECU 2 to the intake throttle valve 14 and a detected signal of an intake air quantity sensor (not shown) are compared. When a distance between the two signals exceeds an allowable range, the malfunction of the intake throttle valve may be increased 14 be determined. Each PM accumulation amount in the DPF 6 at steps S102 and S103, the differential pressure across the DPF 6 calculated. The differential pressure is determined by the differential pressure sensor 8th detected. Here, a correlation between the differential pressure produced by a predetermined amount of exhaust gas passing through the DPF 6 occurs, and a lot of the particles in the DPF 6 are used to detect the PM accumulation amount in the DPF. The correlation is predetermined by experiments and in a memory of the ECU 2 saved as a data map.

When it is determined that the PM accumulation amount is equal to or greater than the reference value M1 at step S102, when it is also determined that the PM accumulation amount is equal to or greater than the reference value M2 at step S103, the operation range becomes through an in 5 determined process determined. If a determination result in the step S102 or S103 is NO, the ECU determines 2 that the regeneration operation is not yet needed. Then the ECU ends 2 the present control routine.

In 5 11, which shows an operation range determination process, the operating state of the internal combustion engine is classified as one of the predetermined ranges A to E according to the temperature of the exhaust gas. The temperature of the inlet exhaust gas to the DPF 6 is through the temperature sensor 71 detected. The temperature of the intake exhaust gas represents the temperature of the exhaust gas. In step S201, the illustrated temperature of the exhaust gas is determined when the temperature thereof is equal to or greater than T1 (550 ° C in the present embodiment). When the temperature of the exhaust gas is equal to or greater than T1 (550 ° C in the present embodiment), the operating state is classified as the region A. Then shows 6 a regeneration control process. In the region A where the temperature of the exhaust gas is high, the particles are spontaneously burned as described above. Thus, the heating operation is not performed.

When the temperature of the exhaust gas is less than T1 at step S201, the temperature of the exhaust gas is determined when the temperature thereof is equal to or greater than T2 (500 ° C in the present embodiment) at step S202. When the temperature of the exhaust gas is equal to or greater than T2, the operating state is classified as the region B. A regeneration control process for area B is in 7 shown. The injection timing delay at which the fuel injection timing is delayed is set at the in 7 shown step S301 performed. In step S302, the ECU determines 2 whether the ECU 2 will end the regeneration operation. The determination of the completion of the regeneration operation is made when the injection timing delay is executed for a predetermined period of time. Steps S301 and S302 are repeated until the ECU 2 determines the completion of the regeneration operation. Alternatively, the ECU determines 2 the termination of regeneration operation when the temperature of the DPF 6 reaches a predetermined temperature (550 ° C in the present embodiment). In this case, the temperature sensor detects 72 the temperature of the outlet exhaust gas and becomes the temperature of the DPF 6 based on the temperature of the outlet exhaust gas from the DPF 6 recorded or estimated.

When the temperature of the exhaust gas is less than T2 at step S202, the temperature becomes of the exhaust gas is determined when the temperature thereof is equal to or greater than T3 (350 ° C in the present embodiment). When the temperature of the exhaust gas is equal to or greater than T3, it is determined that the operating condition corresponds to the range C. A regeneration operation for area C is in 8th shown. In step S311, which is in 8th is shown, the post-injection is performed. In step S312, the ECU determines 2 whether the ECU 2 will end the regeneration operation. The determination of the completion of the regeneration operation is performed in the same manner as in the step S302 in FIG 7 performed. Steps S311 and S312 are repeated until the ECU 2 the completion of the regeneration operation is correct.

When the temperature of the exhaust gas is less than T3 at step S203, the temperature of the exhaust gas is determined when the temperature thereof is equal to or greater than T4 (250 ° C in the present embodiment). When the temperature of the exhaust gas is equal to or greater than T4, the operating condition is classified as the range B. A regeneration operation for the area D is in 9 shown. At the in 9 As shown in step S321, the injection timing delay is performed. At a step S322, the temperature of the oxidation catalyst attached to the DPF 6 is determined, if the temperature of the same is equal to or greater than 350 ° C. The temperature of the oxidation catalyst may be sensed or estimated based on a temperature determined by the temperature sensor 72 measured at the downstream side of the DPF 6 is located. Steps S321 and S322 are repeated until it is determined that the temperature of the oxidation catalyst is equal to or greater than 350 ° C. If the determination result in the step S322 is YES, the post injection is performed in the step S322. Then, in step S324, the ECU determines 2 whether the ECU 2 will end the regeneration operation. The determination of the completion of the regeneration operation is performed in the same manner as in the step S302 in FIG 7 carried out.

Steps S323 and S324 are repeated until the ECU 2 determines the completion of the regeneration operation.

If the temperature of the exhaust gas is less than T4 in step S204, the process proceeds to step S205. In step S205, the ECU determines 2 whether the intake throttle valve 14 works normally. When the intake throttle valve 14 not working normally, the ECU determines 2 in that it is impossible to carry out the regeneration operation. Then the ECU ends 2 the present control routine once. When it is determined that the intake throttle valve 14 operating normally, the operating status is classified as the range E. A regeneration operation for the area E is in 10 shown. In a step S331, which is in 10 is shown, the intake air throttle opening degree decreasing operation by decreasing the opening degree of the intake throttle valve 14 performed to reduce the intake air amount, and also the injection timing delay is performed. In step S332, the ECU determines 2 whether the temperature of the oxidation catalyst is increased to be equal to or greater than 350 ° C. The determination of the temperature of the oxidation catalyst is performed in the same manner as in step S322 in FIG 9 carried out. Steps S331 and S332 are repeated until it is determined that the temperature of the oxidation catalyst is equal to or greater than 350 ° C. If the determination result in the step S232 is YES, the post injection is performed in the step S333. Then, in step S334, the ECU determines 2 whether the ecu 2 will end the regeneration operation. The determination of the completion of the regeneration operation is performed in the same manner as in the step S302 in FIG 7 carried out. Steps S333 and S334 are repeated until the ECU 2 the termination of the Regerationsbetriebs determined.

Similarly, in the present invention, when the intake throttle valve 14 is subject to malfunction, the reference value of the PM accumulation amount for determining the start of the regeneration of the DPF 6 from the reference M1 to the reference M2. Thus, even if the regeneration mode using the intake air throttle opening degree decreasing operation is not performed properly, another regeneration operation such as another heating means is performed before the PM accumulation amount exceeds the allowable amount. Thus, the safe regeneration operation is achieved. Also, the deterioration and the destruction of the DPF and the catalyst due to the overheating during the regeneration is restricted, so that the safety and durability of the exhaust gas purification device is improved. During the regeneration operation, the appropriate heating means is used to perform the heating operation in accordance with the operating range. Thus, the deterioration of the fuel efficiency is minimized. Therefore, the exhaust gas purifying apparatus is enabled with improved safety and reliability.

additional Advantages and modifications will be apparent to those skilled in the art. The invention in its broader meaning should therefore not be the specific details, the representative device and illustrative Examples are limited which are shown and described.

Thus, the exhaust gas purification device for an internal combustion engine 1 has the particle filter 6 for collecting particles of the exhaust gas. The exhaust gas purification device heats the particulate filter 6 through the use of several heating devices 2 . 14 , which is an intake air throttle device 14 exhibit. The exhaust gas purification device detects an amount of the particulate matter in the particulate filter 6 to determine if the amount of particles has a limit to start a regeneration of the particulate filter 6 reached. The exhaust gas purification device classifies an operating state of the internal combustion engine 1 as one of a plurality of predetermined operating ranges. Then, the exhaust gas purification device controls the heating devices 2 . 14 based on the amount of particles and operating range. Further, the exhaust gas purification device detects a malfunction of the intake air throttle device 14 and decreases the limit value when the malfunction of the intake air throttle device 14 is detected.

Claims (9)

Exhaust gas purification device for an internal combustion engine ( 1 ) with: a particle filter ( 6 ) in an exhaust passage ( 12 ) of the internal combustion engine ( 1 ) is located to remove particles of an exhaust gas ( 1 ) of the internal combustion engine ( 1 ) to accumulate and accumulate; a variety of warming agents ( 2 . 14 ) for heating the particulate filter ( 6 ), wherein the plurality of heating means ( 2 . 14 ) an intake air throttle device ( 14 ) located in an intake air passage ( 13 ) of the internal combustion engine ( 1 ) is located; a PM accumulation amount determination device ( 2 ) for detecting an amount of the particles that are in the particulate filter ( 6 ), wherein the PM accumulation amount determining means determines whether the amount of the particulate matters has a limit to start regeneration of the particulate filter (FIG. 6 ) reached; an operating region determining device ( 2 ) for classifying an operating state of the internal combustion engine ( 1 ) as one of a plurality of predetermined operation areas; a regeneration control device ( 2 ) for controlling the plurality of heating means ( 2 . 14 ) based on determination results of the PM accumulation amount determining means (FIG. 2 ) and the operating region determining device ( 2 ), wherein the PM accumulation amount determining means ( 2 ) comprises: a malfunction measuring device ( 2 ) for detecting a malfunction of the intake air throttle device ( 14 ); and a limit value change device ( 2 ) for reducing the limit for starting the regeneration of the particulate filter ( 6 ), wherein the limit value change device ( 2 ) reduces the limit in a case where the malfunction measuring device ( 2 ) the malfunction of the intake air throttle device ( 14 ) detected. An exhaust purification device according to claim 1, wherein said regeneration control means ( 2 ) at least one predetermined one of the plurality of heating means ( 2 . 14 ) controls according to the one of the plurality of predetermined operating ranges than that of the operating range determining means (14). 2 ) the operating state of the internal combustion engine ( 1 ), so that the at least one predetermined one of the plurality of heating means ( 2 . 14 ) the particle filter ( 6 ) is heated so that a temperature of the particulate filter ( 6 ) is increased to be equal to or greater than a combustion temperature of the particles. An exhaust purification device according to claim 1 or 2, further comprising a regeneration stopping device ( 2 ) for preventing the regeneration control device ( 2 ) the plurality of heating means ( 2 . 14 ) for heating the particulate filter ( 6 ) when both of the following conditions are met: the malfunction measuring device ( 2 ) detects the malfunction of the intake air throttle device ( 14 ); the one of the plurality of predetermined operating ranges, as the operating range determining means ( 2 ) the operating state of the internal combustion engine ( 1 ) is an operating region in which the regeneration control device ( 2 ) the intake air throttle device ( 14 ) controls the particulate filter ( 6 ) to heat. An exhaust gas purification device according to claim 1 to 3, wherein: the particulate filter ( 6 ) a catalyst on a surface of the particulate filter ( 6 ) having; and wherein, in a case where the one of the plurality of predetermined operation areas is the one of the operation area designation means (FIG. 2 ) the operating state of the internal combustion engine ( 1 ) is an operating range in which a temperature of the exhaust gas of the internal combustion engine ( 1 ) is equal to or lower than an activation temperature of the catalyst, the regeneration control device ( 2 ) is operated such that: the regeneration control device ( 2 ) the intake air throttle device ( 14 ) and at least one more of the plurality of heating means ( 2 . 14 ) for performing a catalyst heating operation, so that a temperature of the particulate filter ( 6 ) is increased to be equal to or greater than the activation temperature of the catalyst; the regeneration control device ( 2 ) at least one of the plurality of heating means ( 2 . 14 ) for performing a regeneration operation, so that the temperature of the particulate filter ( 6 ) like that is increased to be equal to or greater than a combustion temperature of the particles. An exhaust gas purification device according to claims 1 to 4, further comprising a temperature measuring device ( 71 ) located on an upstream side of the particulate filter ( 6 ) in the exhaust passage ( 12 ) for measuring a temperature of the exhaust gas of the internal combustion engine ( 1 ), wherein the operating region determining device ( 2 ) the operating state of the internal combustion engine ( 1 ) is classified as one of the plurality of predetermined operation ranges according to the temperature of the exhaust gas detected by the temperature measuring device ( 71 ) is measured. An exhaust purification device according to claims 1 to 5, wherein said regeneration control means ( 2 ) the plurality of heating means ( 2 . 14 ) controls so that the plurality of heating means ( 2 . 14 ) the particle filter ( 6 ) is not heated in a case where the one of the plurality of predetermined operating ranges than the operating range determining means ( 2 ) the operating state of the internal combustion engine ( 1 ) is an operating range in which a temperature of the exhaust gas of the internal combustion engine ( 1 ) is equal to or greater than a combustion temperature of the particles. An exhaust purification device according to any one of claims 1 to 6, wherein said plurality of heating means ( 2 ) performs at least one of the following: an injection timing delay; and a post-injection. An exhaust gas purification device according to any one of claims 1 to 6, wherein: said plurality of heating means ( 2 ) an injection control device ( 2 ) for heating the particulate filter ( 6 ) having; and wherein the regeneration control device ( 2 ) the injection control device ( 2 ) controls. An exhaust purification device according to claim 8, wherein said injection control means ( 2 ) performs at least one of the following: an injection timing delay; and a post-injection.