JP2003254138A - Control device for fuel injection device for diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a deterioration in fuel consumption and output power performance of an engine by avoiding further accumulation of a particulate material in filter abnormality. <P>SOLUTION: A particulate filter 14b is provided in an exhaust gas passage 13 of a diesel engine 11. A controller 18 including a memory 18a storing characteristic curve charts 22, 23 is constructed to restrict fuel injection quantity of a fuel injection device 16 with values of the characteristic curve charts 22, 23 corresponding to step in amount of an accelerator pedal. An abnormality detecting means 17 detecting abnormality of the particulate filter 14b is provided and the characteristic curve charts is consist of a normal curve chart 22 indicating fuel injection quantity in a normal traveling condition and an abnormal curve chart 23 indicating fuel injection quantity in an abnormal condition of the particulate filter 14b. The controller 18 selects one of the normal curve chart 22 and the abnormal curve chart 23 according to detection output of the abnormality detection means 17, 27. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a fuel injection device for a diesel engine mounted on a vehicle. More specifically, the present invention relates to a control device for a fuel injection device of a diesel engine in which a particulate filter is provided in an exhaust passage.

[0002]

2. Description of the Related Art Conventionally, a fuel injection device for a diesel engine mounted on a vehicle is controlled by a controller having a memory. In this controller, the detection output of the accelerator sensor that detects the depression amount of the accelerator pedal,
A detection output of a rotation sensor that detects the rotation speed of the engine is connected. Further, the memory of the controller stores a characteristic curve diagram showing the optimum fuel injection amount corresponding to the engine speed and the accelerator pedal depression amount. Then, the controller limits the fuel injection amount of the fuel injection device by the value of the characteristic curve diagram corresponding to the rotation speed of the engine and the depression amount of the accelerator pedal to obtain the optimum engine output during normal running of the vehicle. ing. On the other hand, in recent years, in order to prevent environmental pollution, exhaust gas regulations for vehicle diesel engines have become more stringent, and there is an urgent need to reduce the particulates contained in the exhaust gas. For this reason, measures are taken to reduce the amount of particulates discharged to the outside by providing a particulate filter configured to collect particulates in exhaust gas in the exhaust passage of the engine.

[0003]

However, if only the particulate filter is provided in the exhaust passage of the engine,
If the filter is clogged due to particulates, the exhaust gas pressure of the engine increases, and there is a problem that fuel efficiency and power performance decrease. In order to eliminate this point, an oxidation catalyst that oxidizes NO in the exhaust gas of the engine to NO ₂ is provided in the exhaust passage upstream of the particulate filter, and the particulate matter trapped in the particulate filter by this NO ₂ is removed. A regenerator or the like that is adapted to be oxidized and removed in an exhaust gas temperature range of 250 to 300 ° C. or higher is provided.

However, even if such a regeneration device is provided, regeneration of the particulate filter becomes insufficient, for example, when light load operation continues, and particulates are gradually accumulated and the filter is excessively trapped. There is a risk that an abnormal situation may occur in which the situation becomes a gathering state. If an abnormality such as an over-collection state occurs, the fuel consumption and power performance of the engine deteriorate due to the continuous increase of the exhaust gas pressure, which remains a problem to be solved. The purpose of the present invention is to
It is an object of the present invention to provide a control device for a fuel injection device of a diesel engine, which can prevent further accumulation of particulates when the filter is abnormal and prevent deterioration of fuel efficiency and power performance of the engine.

[0005]

The invention according to claim 1 is
As shown in FIG. 1, a particulate filter 14b configured to collect particulates in exhaust gas flowing into the exhaust passage 13 is provided in an exhaust passage 13 of a diesel engine 11, and an accelerator sensor 21 and an engine rotation sensor are provided. The fuel injection amount of the fuel injection device 16 of the engine 11 is controlled by the controller 18 having the memory 18a that stores the fuel injection amount corresponding to each detected output of 19 as characteristic curve diagrams 22 and 23, and the controller 18 controls the accelerator sensor 21. Fig. 23 is an improvement of the control device of the fuel injection device of the diesel engine configured to limit the fuel injection amount according to the values of the corresponding characteristic curves Figs. The characteristic configuration is that an abnormality detecting means 17 for detecting an abnormality of the particulate filter 14b is provided, and the characteristic curve diagram shows the normal time curve diagram 22 showing the fuel injection amount in the normal traveling state and the abnormal state of the particulate filter 14b. The abnormal state curve diagram 23 and the abnormal state curve diagram 23 indicating the fuel injection amount in the controller 18 are selected. It is configured so as to correspond to the detected accelerator pedal depression amount.

In the control device for the fuel injection device for the diesel engine according to the first aspect of the present invention, the abnormality detecting means 17 detects an abnormality such as clogging of the particulate filter 14b.
If it is detected by the controller 18, the controller 18 determines from the detection output of the abnormality detecting means 17 that the filter 14b is in an abnormal state, and the curve diagram stored in the memory 18a is changed from the normal curve diagram 22 to the abnormal curve diagram. Switch to 23 and select. Then, the controller 18 controls the fuel injection device 16 by comparing the depression amount of the accelerator pedal with the abnormal time curve diagram 23 to prevent the generation of particulates due to the insufficient intake air amount to prevent the abnormal condition of the filter 14b. Avoid further deposition of particulates.

The invention according to claim 2 is the invention according to claim 1, further, as shown in FIG. 2 and FIG. 3, the fuel injection amount shown in the abnormal curve diagram 23 changes to the normal curve diagram 22. It is characterized by comprising a value of 50 to 100% of the indicated fuel injection quantity. In the control device for the fuel injection device for the diesel engine according to the second aspect, the abnormal time curve diagram
Since the fuel injection amount is further reduced as compared with that during normal traveling, it is possible to effectively prevent the generation of particulates due to insufficient intake air amount.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the abnormality detecting means detects the intake pressure in the intake passage 12 of the engine 11.
7, and the controller 18 is configured to select the abnormal curve diagram 23 when the intake pressure sensor 17 during operation of the engine 11 detects a value of 0 or less or 40 kPa or more. In the control device for the fuel injection device of the diesel engine according to the third aspect, an abnormality such as clogging of the particulate filter 14b can be reliably detected by the fluctuation of the intake pressure generated at the time of the abnormality.

The invention according to claim 4 is the invention according to claim 1 or 2, and as shown in FIG.
Reference numeral 7 denotes a first exhaust gas pressure sensor 27a provided in the exhaust passage 13 on the upstream side of the particulate filter 14b and a second exhaust gas pressure sensor 27b provided in the exhaust passage 13 on the downstream side of the particulate filter 14b. When the sensor 27a detects a value of 25 kPa or more, or when the second exhaust gas pressure sensor 27b detects a value of 5 kPa or less, the controller 18 causes the special characteristic curve diagram 23
Is configured to be selected. In the control device of the fuel injection device for the diesel engine according to the fourth aspect, an abnormality such as clogging of the particulate filter 14b can be reliably detected by the exhaust gas pressure before and after the particulate filter 14b that occurs at the time of the abnormality. it can.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the intake port 11b of the cylinder 11a of the diesel engine 11 mounted on the vehicle has an intake passage 12, that is, an intake manifold 12a.
The intake pipe 12b is connected via the exhaust pipe 11b, and the exhaust port 11c of the cylinder 11a is connected to the exhaust pipe 13b via the exhaust passage 13, that is, the exhaust manifold 13a. A case 14 is provided in the exhaust pipe 13b, and the case 14 accommodates an oxidation catalyst 14a and a particulate filter 14b in this order from the exhaust gas upstream side. The oxidation catalyst 14a
Is a monolith catalyst in this embodiment and is constituted by supporting Pt on a honeycomb carrier made of alumina. The filter 14b is a honeycomb filter in this embodiment. Although not shown, the filter 14b has a circular cross section partitioned by a cordierite porous partition wall through which exhaust gas can pass and particulates cannot pass.
These partition walls alternately and substantially seal adjacent inlet portions and outlet portions of a large number of through holes formed in parallel with each other.

In this filter 14b, the filter 14b
The exhaust gas of the engine introduced from the inlet side of the above is configured to be discharged from the outlet side after filtering the particulates contained when passing through the porous partition wall. The above oxidation catalyst 14a has a function of oxidizing NO in the exhaust gas to NO _2, the filter 14b in addition to the functions of collecting particulates in exhaust gases, higher than a predetermined exhaust gas temperature (250 to 300 ° C. or higher) NO _{2 for} particulates
Has a function of removing by oxidation. On the other hand, the engine 11
A fuel injection device 1 for injecting fuel into each cylinder 11a
6 is provided. This fuel injection device 16 is used for the engine 11
Fuel injection nozzle 16a provided in each cylinder 11a
And a fuel injection pump 16c for pressure-feeding fuel to these nozzles 16a via a fuel pressure-feeding pipe 16b.

An abnormality detecting means 17 is provided for detecting an abnormality such as an excessive accumulation of particulates on the particulate filter 14b. The abnormality detecting means 17 in this embodiment is an intake pressure sensor 17 that detects the intake pressure in the intake passage 12 of the engine 11. Further, the engine 11 is provided with an engine rotation sensor 19 that detects the rotation speed of the engine 11. The intake pressure sensor 17 is inserted in the intake pipe b. Each detection output of the intake pressure sensor 17 and the engine rotation sensor 19 is connected to the control input of the controller 18, and the control output of the controller 18 is connected to the fuel injection device 16. Although not shown, the vehicle is provided with an accelerator pedal and an accelerator sensor 21 for detecting the depression amount of the accelerator pedal,
The detection output of the accelerator sensor 21 is connected to the controller 18. The controller 18 is provided with a memory 18a. The memory 18a has a characteristic curve diagram 2 showing the optimum fuel injection amount corresponding to the depression amount of the accelerator pedal.
2, 23 are stored.

The characteristic curve diagram stored in the memory 18a is
The normal-time curve diagram 22 shows the fuel injection amount in a normal state where the particulate filter 14b is normal, and the abnormal-time curve diagram 23 shows the fuel injection amount when the particulate filter 14b is abnormal. The normal-time curve diagram 22 is composed of a plurality of individual normal-time curve diagrams 22a to 22n each showing the fuel injection amount corresponding to the predetermined depression amount of the accelerator pedal in the normal state, and the abnormal-time curve diagram 23 is the particulate filter 14b. 23a to FIG. 23a, each of which is an individual abnormal curve showing a fuel injection amount corresponding to a predetermined depression amount of the accelerator pedal in the abnormal state of FIG.
It consists of 23n. An individual normal time curve diagram in this embodiment corresponding to a predetermined depression amount of the accelerator pedal 22
FIG. 3 shows an example of n, and FIG. 2 shows an example of the individual abnormal curve diagram 23n corresponding to the depression amount.

The individual normal curve diagram 22n shown in FIG. 3 corresponds to a predetermined depression amount of the accelerator pedal. The fuel injection amount is determined by the rotation speed of the engine 11, and the rotation speed of the engine 11 is a predetermined value. When N or more, five different fuel injection amounts (PIM1 to 5) are determined according to the detection output of the intake pressure sensor 17. That is, as in the case of normal running, the intake air amount is sufficient and the intake pressure sensor 17
If the detected output of the controller indicates a high value, the controller 18 follows the line of PIM1 that limits the fuel injection amount to a high value.
Injects fuel. On the other hand, when the amount of intake air is small and the detection output of the intake pressure sensor 17 shows a low value, such as during acceleration, the fuel injection amount is limited to a low value depending on the degree P.
The controller 18 is depicted as injecting fuel according to lines such as IM2-5.

Also, the individual abnormal curve diagram 23n shown in FIG.
Then, the PIM indicating the fuel injection amount when the intake amount is sufficient and the detection output of the intake pressure sensor 17 shows a high value.
1 is the PI shown in the individual normal time curve diagram 22 shown in FIG.
It is set on the same line as M1. On the other hand, when the intake air amount is small and the detection output of the intake pressure sensor 17 shows a low value as during acceleration, 50 to 100% of the lines of PIM2 to 5 shown in the individual normal time curve diagram shown in FIG. Of PIM2'-5 ', which is the value of. That is, the fuel injection amount when the intake amount is small in the abnormal curve diagram 23 is limited to a value that is lower than the fuel injection amount when the intake amount is small in the normal curve diagram 22. And
As a result of this, an abnormal curve diagram based on PIM1 is shown in FIG.
The intervals of PIMs 2 ′ to 5 ′ are drawn so as to be wider than the intervals of PIMs 2 to 5 in the normal time curve diagram 22 based on PIM 1.

The controller 18 is configured to select one of the normal curve diagram 22 and the abnormal curve diagram 23 according to the detection output of the abnormality detection means 17. In this embodiment, when the intake pressure sensor detects a value of 0 or less or 40 kPa or more, it is determined that the filter 14b is in the abnormal state, the controller selects the abnormal time curve diagram 23, and the intake pressure sensor 17 determines the other. When the value of is detected, the controller 18 determines that the filter 14b is in the normal state.
Is configured to select the normal time curve diagram 22, and the controller 18 determines both the accelerator pedal depression amount and the engine 11 rotation speed and the selected characteristic curve diagrams 22 and 23. Fuel injection device 1 according to the values of the corresponding characteristic curves 22 and 23 of FIG.
The fuel injection amount of No. 6 is limited to obtain an optimum output according to the driving situation.

The operation of the control device of the fuel injection device for the diesel engine thus configured will be described. The control device of the fuel injection device controls the fuel injection device 16 according to the depression amount of the accelerator pedal, and maintains the rotation speed of the engine 11 according to the depression amount. During normal traveling of the vehicle in which there is no abnormality in the particulate filter 14b, the controller 18 detects the output of the accelerator sensor 21 that detects the rotation speed of the engine 11 and the depression amount of the accelerator pedal, and the normal curve diagram that limits the fuel injection amount. Two
2 is compared and the corresponding fuel injection amount of the normal curve diagram 22 is determined to control the fuel injection device 16.

On the other hand, when an abnormality such as clogging of the particulate filter 14b occurs, the intake pressure sensor 1
The detection output of 7 deviates from the normal value and is 0 or less or 40 kP.
A value of a or more is detected. Then, the controller 18 determines that the filter 14b is in an abnormal state, and switches the curve diagram stored in the memory 18a for limiting the fuel injection amount from the normal curve diagram 22 to the abnormal curve diagram 23 and selects it. Then, the controller 18 compares both the depression amount of the accelerator pedal and the rotation speed of the engine 11 with the selected abnormal curve diagram 23, and limits the fuel injection amount of the fuel injection device 16 by the corresponding values. To do. Here, the line of PIM2'-5 'which shows the line at the time of acceleration of the abnormal time curve diagram is 50-100% of the value of the line of PIM2-5 shown in the normal time curve diagram 22, so the controller 18 When the particulate filter is abnormal, the fuel injection device 16 is controlled so as to further reduce the fuel injection amount as compared with that during normal traveling, to prevent the generation of particulates due to insufficient intake air volume, and to prevent the particulates when the filter 14b is abnormal. Avoid further deposition of curate.

The fuel injection system 1 according to the normal curve diagram 22 shown in FIG.
FIG. 4 shows a comparison between the case where 6 is controlled and the case where the fuel injection device 16 is controlled according to the abnormal curve diagram 23. When controlled according to the normal time curve diagram 22, the lines of PIM2 to 5 are relatively close to each other during acceleration, and therefore, when the accelerator pedal is depressed, the fuel injection amount Q of the engine is also proportional to the depression amount. As shown by the broken line, it rises rapidly and is maintained at a predetermined value. In accordance with this, the engine rotation speed NE also rapidly rises as shown by the broken line and is maintained at the rotation speed corresponding to the depression amount of the accelerator pedal.

On the other hand, when controlled according to the abnormal curve diagram 23, the lines of PIM2'-5 'during acceleration in FIG. 2 are the PIM2 shown in the normal curve diagram 22 in FIG.
Since the value is lower than ˜5, when the accelerator pedal is depressed, the fuel injection amount Q of the engine gradually rises and is maintained at a predetermined position as shown by the solid line. Accordingly, the engine rotation speed NE also gradually increases as shown by the solid line, but the finally obtained rotation speed is maintained at the same rotation speed corresponding to the accelerator pedal depression amount as in the case of the normal curve diagram 22. Be drunk Therefore, when the controller 18 determines that there is an abnormality based on the detection output of the abnormality detecting means 17, a slight delay occurs during acceleration, but in the subsequent steady state, the same engine output as when the normal time curve diagram 22 is used. Can be obtained.

In the above-described embodiment, the case where the abnormality detecting means is the intake pressure sensor 17 has been described. However, as shown in FIG. 5, the abnormality detecting means 27 includes the exhaust passage on the upstream side of the particulate filter 14b. The first exhaust gas pressure sensor 27a provided in No. 13 and the second exhaust gas pressure sensor 27b provided in the exhaust passage 13 on the downstream side of the particulate filter 14b may be used. That is, the abnormality detecting means 27 shown in FIG. 5 is the first and second exhaust gas pressure sensors 27a and 27b provided before and after the particulate filter 14b in the exhaust passage 13. These exhaust gas pressure sensors 27a and 27b are respectively inserted in the exhaust pipes 13b before and after the case 14, and are configured to detect the exhaust gas pressures before and after the filter 14b. First and second exhaust gas pressure sensors 27a, 27b and engine rotation sensor 1
Each detection output of 9 is connected to the control input of the controller 18, and the control output of the controller 18 is connected to the fuel injection device 16. In this case, the controller 18 selects the abnormal time curve diagram 23 when the first exhaust gas pressure sensor 27a detects a value of 25 kPa or more, or when the second exhaust gas pressure sensor 27b detects a value of 5 kPa or less. Preferably.

[0022]

As described above, according to the present invention, the abnormality detecting means for detecting the abnormality of the particulate filter is provided, and the characteristic curve diagram is the normal curve diagram showing the fuel injection amount in the normal running state. An abnormal curve diagram showing the fuel injection amount when the particulate filter is abnormal, and the controller selects either the normal curve diagram or the abnormal curve diagram according to the detection output of the abnormality detection means to select the accelerator pedal. Since it is configured to correspond to the depression amount, when an abnormality such as clogging of the particulate filter occurs, the controller determines from the detection output of the abnormality detection means that the filter is in an abnormal state, and the abnormal curve diagram The fuel injection device is controlled so that the fuel injection amount is further reduced compared to that during normal driving by switching to the accelerator pedal and comparing it with the accelerator pedal depression amount. To. As a result, it is possible to prevent the generation of particulates due to the insufficient intake air amount, and it is possible to avoid the deterioration of the fuel efficiency and power performance of the engine due to the further accumulation of particulates when the filter is abnormal.

In this case, the fuel injection amount shown in the abnormal curve diagram is 50 to 10 of the fuel injection amount shown in the normal curve diagram.
It preferably consists of a value of 0%. Further, the abnormality detecting means may be either an intake pressure sensor that detects the intake pressure in the intake passage of the engine or an exhaust gas pressure sensor provided before and after the particulate filter in the exhaust passage.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a control device according to an embodiment of the present invention.

FIG. 2 is an abnormal curve diagram of the apparatus.

FIG. 3 is a normal curve diagram of the apparatus.

FIG. 4 is a diagram showing a relationship between an accelerator pedal depression amount, a fuel injection amount, and an engine rotation speed in a normal state and an abnormal state in the apparatus.

FIG. 5 is a block diagram corresponding to FIG. 1, showing another control device of the present invention.

[Explanation of symbols]

11 diesel engine 12 Intake passage 13 Exhaust passage 14b Particulate filter 16 Fuel injection device 17 Intake pressure sensor (abnormality detection means) 18 Controller 18a memory 22 Normal curve diagram (Characteristic curve diagram) 23 Abnormal curve diagram (Characteristic curve diagram) 27a First exhaust gas pressure sensor (abnormality detection means) 27b Second exhaust gas pressure sensor (abnormality detection means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayoshi Komiya             3-1, Hinodai, Hino City, Tokyo 1 Hino             Inside the automobile corporation F term (reference) 3G084 AA01 BA13 DA26 DA28 EA08                       EA11 EB08 FA10 FA11 FA34                 3G090 AA02 DA01 DA03 DA04 DA20                       EA02 EA04                 3G301 HA02 JB00 JB07 MA11 NA08                       NB04 NC02 PA07Z PD14Z                       PE01Z PF03Z

Claims (4)

[Claims] An exhaust passage (13) for a diesel engine (11)
A particulate filter configured to collect particulates in the exhaust gas flowing into the exhaust passage (13)
(14b) is provided, a controller having a memory (18a) that stores the fuel injection amount corresponding to each detection output of the accelerator sensor (21) and the engine rotation sensor (19) as a characteristic curve diagram (22, 23) ( 18) Fuel injection device for the engine (11)
(16) the fuel injection amount is controlled, the controller (18) the characteristic curve diagram corresponding to the accelerator sensor (21) (22,
In the control device of the fuel injection device of the diesel engine configured to limit the fuel injection amount by the value of 23), an abnormality detection means (17, 27) for detecting an abnormality of the particulate filter (14b) is provided. The characteristic curve diagram is a normal time curve diagram showing the fuel injection amount in a normal running state (22) and the particulate filter.
Abnormal curve diagram showing the fuel injection amount at the time of abnormality of (14b)
(23), the controller (18) is a detection output of the abnormality detection means (17, 27) the normal curve diagram (22) and the abnormal curve diagram
Select any one of (23) to select the accelerator sensor (21)
A control device for a fuel injection device of a diesel engine, which is configured to correspond to a depression amount of an accelerator pedal detected by the. 2. The fuel injection amount shown in the abnormal curve diagram (23) is 50 to 10 of the fuel injection amount shown in the normal curve diagram (22).
The control device for a fuel injection device of a diesel engine according to claim 1, wherein the control device has a value of 0%. 3. The intake passage of the engine (11), wherein the abnormality detecting means is
An intake pressure sensor (17) for detecting the intake pressure in (12), wherein the intake pressure sensor (17) during operation of the engine (11) is 0.
The control device for a fuel injection device for a diesel engine according to claim 1 or 2, wherein the controller (18) is configured to select the abnormal curve diagram (23) when a value below or above 40 kPa is detected. 4. A first exhaust gas pressure sensor (27a) provided in the exhaust passage (13) on the upstream side of the particulate filter (14b), and the particulate filter (14b).
A second exhaust gas pressure sensor (27b) provided in the exhaust passage (13) on the downstream side, when the first exhaust gas pressure sensor (27a) detects a value of 25 kPa or more, or the second exhaust gas pressure sensor ( The control device for the fuel injection device of the diesel engine according to claim 1 or 2, wherein the controller (18) is configured to select the special characteristic curve diagram (23) when 27b) detects a value of 5 kPa or less.