JPS6073009A - Exhaust particle treating device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make a trap regenerating device compact, by supplying air discharged from a supercharger and exhaust gas from an upstream side of a burner device through a selector valve. CONSTITUTION:In a light load operating area of an engine where oxygen content in an exhaust gas in 15% or more, for example, a vacuum air is supplied to one flow control valve 27 by an electromagnetic selector valve 29, and the exhaust gas is fed through a second combustion air supply passage 25 to an air- fuel mixture supply passage 21. Further, in the other operating areas, the vacuum air is supplied to the other flow control valve 26, and an air discharged from a compressor 14 is fed through a first combustion air supply passage 24 to the air-fuel mixture supply passage 21. Thus, it is possible to make a trap regenerating device compact.

Description

[Detailed description of the invention] Technical fields> The present invention relates to an exhaust particulate treatment device for an internal combustion engine.

<Prior art> The exhaust of internal combustion engines, such as diesel engines, contains many exhaust particulates whose main component is carbon.
This particulate is collected by a trap provided in the middle of the exhaust passage to prevent the particulate from dispersing to the outside.

A conventional example of such an exhaust particulate treatment device is shown in FIG. 1 (see Japanese Patent Laid-Open No. 115809/1983).

That is, a trap 5 for collecting particulates is connected via an exhaust pipe 4 to the outlet of a turbine 3 of a supercharger 2 connected to an exhaust manifold 1 of an internal combustion engine, and this trap 5 collects particulates contained in the exhaust gas. Collect.

Then, when a predetermined amount of particles are collected in the trap 5,
A burner device 6 provided upstream of the trap 5 is operated to heat and burn the particulates stored in the trap 5, thereby regenerating the trap 5.

Further, a mixture of fuel supplied from a fuel injection valve T and air supplied from an engine-driven air pump 8 is introduced into the burner device 6 via a mixture supply passage 9.

However, in such a conventional exhaust particulate treatment device, air is supplied from the air pump 8, so if the trap 5 is to be regenerated in all operating ranges of the engine, the air pump 8 that supplies air to the burner device 6 must have a large capacity. There was a problem in that the playback device for Sitrap 5 was large.

Furthermore, since the large-capacity air pump 8 is driven by the engine even when the burner device 6 is not operating, the air pump 8 in this case places an unnecessary load on the engine, leading to a decrease in engine output or deterioration of fuel efficiency. There was a point.

<Objective of the Invention> In view of such conventional problems, an object of the present invention is to reduce the size of a trap regeneration device, and to prevent a decrease in engine output and deterioration of fuel efficiency.

<Structure of the Invention> Therefore, in the present invention, a first combustion air supply passage that supplies air discharged from the compressor of the supercharger to the mixture supply passage, and a first combustion air supply passage that supplies air discharged from the compressor of the supercharger to the mixture supply passage; a second combustion air supply passage that supplies exhaust gas from the exhaust passage; and a switching device that selectively switches between these two passages;
It was designed to provide a.

<Example> The present invention will be described below based on an example not shown in FIGS. 2 and 3.

Engine intake manifold 11 and exhaust manifold 12
A compressor 14 and a turbine 15 of a supercharger 13 are respectively interposed in the gathering part of the engine, thereby forming an internal combustion engine with a supercharger. The clean side of an air cleaner 17 is connected to the inlet of the compressor 14 via an intake duct 16, and the trap 19 similar to the conventional one is connected to the exhaust outlet of the turbine 15 via an exhaust passage 18. A burner device 20 is installed upstream of this trap 19. An open end of a mixture supply passage 21 for supplying a combustion mixture to the burner device 20 is exposed inside the burner device 20 . A fuel injection valve 22 is provided at the upstream end of the air-fuel mixture supply passage 21 .

The mixture supply passage 21 near the fuel injection valve 22 is branched,
The upstream end of this branch passage 23 is connected to the downstream ends of first and second combustion air supply passages 24,25.

The upstream end of the first combustion air supply passage 24 is connected from the outlet of the compressor 14 of the supercharger 13 to the intake manifold 11.
The upstream end of the second combustion air supply passage 25 connects to the exhaust manifold 12.
The turbine 15 is connected to an exhaust passage 18 leading to the turbine 15. Furthermore, flow control valves 26 and 27 are interposed in the first and second combustion air supply passages 25. The downstream ends of negative pressure introduction pipes 28a, 28b that introduce negative pressure air into the flow control valves 26.27 are connected to these flow rate control valves 26.27, and the upstream ends of the negative pressure introduction pipes 28a, 28b are connected to electromagnetic It is connected to each outlet of the type switching valve 29, respectively.

The electromagnetic switching valve 29 receives a signal from a control device (not shown) and supplies negative pressure air to one of the flow control valves 27 in a low engine load operating region where the residual oxygen in the exhaust is, for example, 15% or more. Exhaust gas is introduced into the mixture supply passage 21 via the second combustion air supply passage 25, and in other operating regions, negative pressure air is supplied to the other flow control valve 26 and discharged from the compressor 14. The combustion air is introduced into the air-fuel mixture supply passage 21 via the first combustion air supply passage 24. Further, the control device outputs an actuation signal to the electromagnetic switching valve 29 based on the rotational speed and load of the engine and a preset operating state of the engine.

30 is a negative pressure controller that duty-controls the amount of negative pressure air introduced from a negative pressure supply source (not shown) through the negative pressure passage 31 to the flow rate control valves 26 and 27; 32 is a negative pressure controller of the burner device 20; It is a glow plug for ignition. Here, the flow rate control valves 26 and 27, the electromagnetic switching valve 29, and the control device constitute a switching device.

Next, the operation of such an exhaust particulate processing device will be explained.

The exhaust gas that drove the turbine 15 of the supercharger 13 is in the exhaust passage 1
8 and is introduced into a trap 19, where the exhaust particulates such as carbon contained in the exhaust gas are collected and the exhaust gas is released into the atmosphere in a clean state.

When it is determined that a predetermined amount or more of exhaust particles have been collected in the trap 19, the differential pressure across the trap 19 relative to the second-stream exhaust pressure detected by a pressure sensor (not shown), for example, is detected by a pressure sensor (not shown). When the exhaust gas temperature reaches a predetermined value or more and is detected by a temperature sensor (not shown) in the trap 19, the burner device 20
operates to heat and burn the exhaust particulates collected in the trap 19, thereby regenerating the trap 19.

When the trap 19 is regenerated, the rotational speed and load of the engine are detected, and the control device outputs an activation signal to the electromagnetic switching valve 29 based on these detected values and a preset operating state of the engine. That is, when the residual oxygen concentration in the exhaust gas is, for example, 15% or more, the electromagnetic switching valve 29
By supplying negative pressure to one flow control valve 2T, the flow control valve 27
is controlled, and exhaust gas containing a large amount of residual oxygen is supplied to the air-fuel mixture supply passage 21 via the second combustion air supply passage 25 and the branch pipe 23. Then, the mixture of fuel and exhaust gas injected from the fuel injection valve 22 is supplied to the burner device 20 and ignited and burned by the ignition glow plug 32.

In the region (A) of FIG. 3 (high load operation region), the flow rate control valve 26 is controlled to direct the air pressurized by the compressor 14 of the supercharger 13 to the first combustion air supply passage 24 and the branch pipe. The mixture is supplied to the air-fuel mixture supply passage 21 via 23.

Further, in the region shown in FIG. 3(B), air can be supplied by appropriately delaying the fuel injection timing of the engine only while the burner device 20 is in operation.

That is, when the fuel injection timing is delayed, the engine output decreases as shown by the broken line in FIG. The combustion air can be supplied to the mixture supply passage 21 via the combustion air supply passage 24 and the branch pipe 23. At this time, it is possible to supply pressurized air from the compressor 14 to the inner regions of the (B) region and (C) region, but normally (B)
) area (hatched area in Figure 3).

As described above, exhaust gas or air with a high oxygen concentration is supplied to the burner device 20 in almost the entire operating range of the engine to heat and burn the particulates collected in the trap 19. Since there is no need for an air pump, the wrap reproducing device can be made more compact. Furthermore, since the air pump is not required, it is possible to prevent a decrease in the output of the engine that is the driving source for the air pump and to prevent deterioration in fuel efficiency.

Note that the exhaust volume and air volume supplied to the burner device 20 can be optimally controlled by controlling the negative pressure controller 30 based on a duty ratio stored in advance in a control device (not shown).

<Advantageous Effects of the Invention> As explained above, in the present invention, the air discharged from the compressor of the supercharger and the exhaust air from the exhaust passage are appropriately selected and supplied to the burner device, so an air pump is not required. This makes it possible to downsize the trap regeneration device. Further, since an air pump is not required, a decrease in the output of the engine that is the driving source for the air pump and a deterioration in fuel efficiency can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a conventional example of an exhaust gas particle processing device, FIG. 2 is a schematic diagram showing an embodiment of the present invention, and FIG. 3 is a characteristic diagram showing the operating range of the burner device. 12...Exhaust manifold 13...Supercharger 14.
...Compressor 19...Trap 20...Burner device 21...Mixture supply passage 24...First
Combustion air supply passage 25...Second combustion air supply passage 26.27...Flow rate control valve 29...Solenoid switching valve Patent applicant Nissan Motor Co., Ltd. Agent Patent attorney Fujio Sasashima Procedures Amendment letter Yaributsu January 30, 1980 Kazuo Wakasugi, Commissioner of the Patent Office ■, minor incident indication 1982 Patent Application No. 178320 2, name of invention Internal combustion engine exhaust particulate treatment device 3.1ii Correct Relationship with the patent case Patent applicant address 2 Takaracho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture Name (
399) Nissan Motor Co., Ltd. Representative: Shun Ishiya 4, Agent Address: Daisan Mori Building, 1-4-10 Nishi-Shinbashi, Minato-ku, Tokyo 508-9577 Name: Patent Attorney (7833) Fujio Sasashima 5, Column 6 for detailed explanation of the invention subject to amendment, content of amendment (1) In the first line of page 8 of the specification, “(engine low load operation regime @
)] is corrected to ``(+lt'l area below the broken line)j. , j is divided by Pill.
It is best to carry out this process in the l area (hatched area in Fig. 3). j is corrected to read, ``In the portion where both areas (area and Ic) overlap (hatched area in FIG. 3), it is preferable to perform the control method for area (Y3) preferentially.''that's all

Claims (1)

[Claims] The trap includes a trap installed in an exhaust passage to collect particulates in the exhaust gas, and a burner device that heats and burns the exhaust particulates collected by the trap, and supplies the combustion mixture to the burner device. In a supercharged internal combustion engine that supplies air through a supply passage, a first air-fuel mixture supply passage supplies air discharged from a compressor of the supercharger to the mixture supply passage.
a second combustion air supply passage that supplies exhaust gas from an exhaust passage upstream of the burner device to the mixture supply passage; and a switching device that selectively switches between these two roads. An exhaust particulate treatment device for an internal combustion engine, characterized in that: