JPH0642411A - Exhaust re-circulating device - Google Patents

Abstract

PURPOSE:To prevent abrasion of a piston ring and a cylinder liner from increasing in comparison with that of non-exhaust re-circulation, in a device for re- circulating exhaust air in an auxiliary chamber type internal combustion engine provided with an auxiliary combustion chamber. CONSTITUTION:An exhaust re-circulating device. for re-circulating exhaust gas in an auxiliary chamber type internal combustion engine provided with an auxiliary combustion chamber, is provided with a recirculating passage 60 for returning exhaust gas in an exhaust passage 40 into an auxiliary combustion chamber 21, a control valve 61 for controlling the amount of exhaust gas which flows in the exhaust gas re-circulating passage 60, and a valve 62 for preventing reflux exhaust gas from making reverse flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for a subchamber internal combustion engine.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional auxiliary chamber type internal combustion engine.
The piston 11 slides on the inner surface of the cylinder liner 12.
The supply air is introduced into the main combustion chamber 20 from the supply passage 30 via the supply valve 31, and the auxiliary combustion chamber 21 in which the fuel injection valve 22 is mounted communicates with the main combustion chamber 20. Exhaust gas from the main combustion chamber 20 is discharged to the atmosphere from the exhaust passage 40 via the exhaust valve 41. Further, an exhaust gas recirculation passage 50 that connects the exhaust gas passage 40 and the air supply passage 30 is provided, and an exhaust gas recirculation device that mixes a part of the exhaust gas into the intake air via the control valve 51 is provided.

Next, the operation of the conventional example will be described. A piston ring 13 is provided on the piston 11 and slides on the inner surface of the cylinder liner 12. In such exhaust gas recirculation system of conventional type with, the charge air exhaust is mixed is allowed to reduce the supplied NO _x generated in direct combustion chamber.

[0004]

As described above, in the conventional example, the intake air is mixed with the exhaust gas in the intake passage 30 and introduced into the main combustion chamber 20 through the intake valve 31, so that the intake air and the exhaust gas are not mixed. Mixing is well done. As a result, the exhaust gas is also introduced near the sliding portion of the piston 11 and the piston ring 13 on the inner surface of the cylinder liner 12 of the main combustion chamber 20,
Soot, sulfuric acid, etc. in the exhaust adhere to the sliding surface, and the piston ring 13 and the cylinder liner 12 are greatly worn.

An object of the present invention is to solve the above-mentioned problems of the conventional device and prevent an increase in wear of the piston ring and the cylinder liner in an exhaust gas recirculation in an auxiliary chamber type internal combustion engine having an auxiliary combustion chamber. To provide an exhaust gas recirculation device.

[0006]

The exhaust gas recirculation system of the present invention is an auxiliary chamber type internal combustion engine having an auxiliary combustion chamber 2 for returning exhaust gas from the main combustion chamber to the exhaust passage 40 to the combustion chamber for exhaust gas recirculation. What is performed, an exhaust gas recirculation passage 60 for returning the exhaust gas of the exhaust passage to the auxiliary combustion chamber 21, control valves 61, 71 for controlling the amount of exhaust gas flowing through the exhaust gas recirculation passage, and a reverse flow of the recirculated exhaust gas are prevented. It is characterized by having valves 62 and 72.

[0007]

In the present invention, the exhaust gas recirculated to the auxiliary combustion chamber exists in the auxiliary combustion chamber and in the vicinity of the auxiliary combustion chamber in the main combustion chamber. As a result, almost no exhaust gas is introduced into the piston on the inner surface of the cylinder of the main combustion chamber and its sliding portion of the piston ring, and wear on the piston ring and cylinder liner increases compared to the non-exhaust gas recirculation type. There is nothing to do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In the first embodiment of the invention shown in FIG.
An exhaust gas recirculation passage 60 connecting the exhaust passage 40 and the auxiliary combustion chamber 21 is provided, and a control valve 61 and an automatic check valve 62 are provided in the exhaust gas recirculation passage 60. By controlling the opening / closing time of the control valve 61, the recirculation amount of exhaust gas to the combustion chamber can be increased or decreased, and by providing the automatic check valve 62, the working gas from the auxiliary combustion chamber 21 to the exhaust passage 40 can be changed. Does not flow backwards.

FIG. 2 shows a second embodiment of the present invention. A control valve 71 and a valve 72 that mechanically opens and closes are provided in an exhaust gas recirculation path 70 that connects the exhaust passage 40 and the auxiliary combustion chamber 21. The valve 72 that mechanically opens and closes is closed during the combustion period when the pressure in the auxiliary combustion chamber 21 is high, and the working gas does not flow back to the exhaust passage 40.

[0010]

Since the exhaust gas recirculation system of the present invention is constructed as described above, the exhaust gas from the exhaust passage 40 is discharged from the auxiliary combustion chamber 21.
The exhaust gas is present in the auxiliary combustion chamber 21 and in the main combustion chamber 20 in the vicinity of the auxiliary combustion chamber 21 because it is recirculated to the auxiliary combustion chamber 21. As a result, the piston 1 on the inner surface of the cylinder liner 12 of the main combustion chamber
1 does not exist near the sliding portion of the piston ring 13 and wear of the piston ring 13 and the cylinder liner 12 does not increase as compared with a non-exhaust gas recirculation engine. Further, the recirculated exhaust gas is injected into the fuel injector 2
Since the fuel injected from No. 2 is mostly present near the auxiliary combustion chamber 21 in which the fuel is burned and the auxiliary combustion chamber 21 of the main combustion chamber 20, it is possible to obtain a larger NO _x reduction effect than before even with the same recirculation amount of exhaust gas. .

[Brief description of drawings]

FIG. 1 is an overall view according to a first embodiment of the present invention,

FIG. 2 is an overall view of a second embodiment of the present invention,

FIG. 3 is a diagram of a conventional sub-chamber internal combustion engine,

[Explanation of symbols]

21 ... Sub-combustion chamber, 40 ... Exhaust passage, 60 ... Exhaust gas recirculation passage, 61 ... Control valve, 62 ... Automatic check valve, 72 ... Mechanically opened / closed valve.

Claims (1)

[Claims] 1. A sub-chamber internal combustion engine having a sub-combustion chamber (21), wherein exhaust gas discharged from the main combustion chamber to an exhaust passage (40) is returned to the combustion chamber and exhaust gas recirculation is performed. Exhaust gas recirculation passage (6
0) (70), control valves (61) (71) for controlling the amount of exhaust gas flowing through the exhaust gas recirculation passage, and valves (62) (72) for preventing reverse flow of the recirculated exhaust gas. Exhaust gas recirculation device.