JPH08246890A - Exhaust device for static pressure supercharging type internal combustion engine - Google Patents

Abstract

PURPOSE: To reduce fuel specific consumption by enhancing a utilization factor of exhaust energy in the whole operation area of a static pressure supercharging type internal combustion engine. CONSTITUTION: The inside of an exhaust pipe 30 is partitioned into an exhaust gas chamber 31 and a pressure gas chamber 32 by a flexible film 11. At low load time, a regulating valve 13 is opened, and pressure gas is introduced into the pressure gas chamber 32, and the flexible film 11 is bent, and the volume of the exhaust gas chamber 31 is reduced, and dynamic pressure energy is increased. At high load time, the pressure gas in the pressure gas chamber 32 is discharged, and the volume of the exhaust gas chamber 31 is made large, and static pressure energy is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a static pressure supercharged internal combustion engine.

[0002]

2. Description of the Related Art In a large diesel engine, exhaust gas from a cylinder is temporarily stored in a large-capacity exhaust pipe, its dynamic pressure energy is converted into static pressure energy, and then this exhaust gas is guided to a supercharger. The static pressure supercharging system that drives this is often adopted.

FIG. 3 shows a conventional example of such a static pressure supercharged large diesel engine. In FIG. 3, 1 is an engine cylinder, 2 is an air supply chamber, 3 is an exhaust pipe, 8 is an exhaust branch pipe connecting each cylinder 1 and the exhaust pipe 3, and 9 is each cylinder 1 and the air supply chamber 2. Connected air supply branch pipe, 10 is a supercharger,
It consists of a turbine 10A and a compressor 10B.

During operation of the engine, the exhaust gas discharged from the cylinder 1 is introduced into the large-capacity exhaust pipe 3 through the exhaust branch pipe 8, where the dynamic pressure energy is converted into static pressure energy.

This exhaust gas passes through the exhaust passage 5 and the supercharger 10
The turbine 10A is driven and driven by the turbine 10A
Rotate the compressor 10B that is coaxial with. The supply air pressurized by the compressor 10B of the supercharger 10 is supplied to each cylinder 1 at an appropriate timing via the supply chamber 2 and the supply branch pipe 9.

[0006]

FIG. 4 shows the engine output level (average effective pressure level) and the exhaust energy ratio, that is,
The relationship between the ratio of static pressure energy and dynamic pressure energy when the total exhaust energy is 1 is shown.

As is apparent from FIG. 4, the proportion of the static pressure energy increases as the engine output level increases, but the volume of the exhaust pipe 3 should be small in order to effectively utilize the dynamic pressure energy at a low output level. On the other hand, in order to effectively use the static pressure energy, it is necessary to increase the volume of the exhaust pipe 3 and reduce the pressure fluctuation of the exhaust gas.

However, since the volume of the conventional exhaust pipe 3 is set on the basis of the maximum output of the engine, when the engine output level is low, the volume of the exhaust pipe 3 becomes excessive and the dynamic pressure energy is increased. Shortage will cause the engine output to decrease and the fuel consumption rate to increase.

An object of the present invention is to increase the utilization rate of exhaust energy in the entire operating range of the engine and reduce the fuel consumption rate without lowering its output.

[0010]

SUMMARY OF THE INVENTION The present invention has been invented to solve the above-mentioned problems, and its gist is that exhaust gas from a cylinder is temporarily stored in a large-capacity exhaust pipe. In an exhaust device for a static pressure supercharged internal combustion engine that guides and drives a supercharger, the inside of the exhaust pipe is partitioned by a flexible film into an exhaust gas chamber and a pressure gas chamber, and the exhaust gas chamber is The exhaust system for a static pressure supercharged internal combustion engine is characterized in that the pressure gas chamber is connected to a pressure gas supply source through a regulating valve while being connected to a cylinder and a supercharger.

[0011]

In the present invention, because of the above-mentioned structure, when the pressure valve is opened and the pressure gas is introduced into the pressure gas chamber when the engine load is low, the flexible membrane is pushed out toward the exhaust gas chamber side. The volume of the exhaust gas chamber is reduced. As a result, the utilization rate of the dynamic pressure energy is increased, the supply amount is increased, good combustion is obtained, and the fuel consumption rate is reduced.

When the gas pressure in the pressure gas chamber is released when the engine is under heavy load, the flexible film is pushed out toward the pressure gas chamber by the exhaust gas pressure in the exhaust gas chamber, and the volume of the exhaust gas chamber increases to a predetermined set volume. To do. As a result, the utilization rate of the static pressure energy is increased, the air supply amount is increased, and the low fuel consumption rate can be maintained.

[0013]

FIG. 1 shows an exhaust system for a static pressure supercharged internal combustion engine according to one embodiment of the present invention. (A) is a system diagram and (B) is
It is sectional drawing which follows the BB line of (A). In FIG. 1, 1
Is an engine cylinder, 2 is an air supply chamber, 9 is an air supply branch pipe connecting the air supply chamber 2 and the cylinder 1, 30 is an exhaust pipe, 8 is an exhaust branch pipe, 10 is a supercharger, and a turbine 10A and This turbine 10A
It consists of a compressor 10B that is rotated by.

A flexible film 11 made of a thin metal film is provided inside the exhaust pipe 30 along the longitudinal direction thereof, and the interior of the exhaust pipe 30 is partitioned by the flexible film 11 to form an exhaust gas chamber 31. A pressure gas chamber 32 is formed. This flexible film 11 is shown in FIG. 1 (B).
As shown in (3), it is attached with a bending allowance so that it can be easily bent when the pressure gas is introduced into the pressure gas chamber 32. As the flexible film 11, a material other than a metal film can be used as long as it has heat resistance and flexibility.

Exhaust gas is introduced from each cylinder 1 into the exhaust gas chamber 31 through the exhaust branch pipe 8, and the exhaust gas chamber 31 is connected to the turbine 10A of the supercharger 10 through an exhaust passage 33. . The pressure gas chamber 32 is connected to a pressure gas supply source such as an air compressor (not shown) via the pressure gas passage 12,
Pressure gas such as compressed air is introduced.
Reference numeral 13 is an adjusting valve for adjusting the pressure in the pressure gas chamber 32 by switching between the pressure gas passage 12 and the pressure gas chamber 32 and between the pressure gas chamber 32 and the discharge pipe 14.

When the engine is operating, however, the exhaust gas discharged from each cylinder 1 flows into the exhaust gas chamber 31 through the exhaust branch pipe 8. When the engine is under a low load, the adjusting valve 13 is opened to the pressure gas chamber 32 from the pressure gas supply source to the pressure gas passage.
Pressure gas is introduced via 12. Then, this pressure gas pushes the flexible film 11 toward the exhaust gas chamber 31 side and the exhaust gas chamber 31
The internal volume is reduced.

As a result, the exhaust gas that has flowed into the exhaust gas chamber 31 is guided to the turbine 10A of the supercharger 10 and drives it while maintaining a large dynamic pressure energy. Then, the driving energy of the compressor 10B increases, so that the supply air is sufficiently pressurized and sent to the cylinder 1, and good combustion and a low fuel consumption rate are obtained.

Further, when the engine is under a heavy load, the pressure gas chamber 32 is communicated with the discharge pipe 14 by operating the regulating valve 13 to shut off the pressure gas passage 12. This allows the pressure gas chamber
The pressure in 32 becomes atmospheric pressure, and the flexible membrane 11 is pushed out to the pressure gas chamber 32 side by the pressure of the exhaust gas in the exhaust gas chamber 31, and the volume of the exhaust gas chamber 31 is increased.

As a result, the volume of the exhaust gas chamber 31 becomes sufficiently large, the pressure in the exhaust gas chamber 31 is leveled, and the pressure fluctuation is reduced. As a result, the static pressure energy of the exhaust gas is efficiently utilized in the supercharger 10, a large amount of supercharged air is supplied to the cylinder 1, and good combustion and a low fuel consumption rate are obtained.

FIG. 2 shows the relationship among the engine load, the exhaust gas chamber volume, the exhaust gas chamber pressure, the pressure gas chamber pressure, and the fuel consumption rate. As shown in FIG. 2, the pressure in the exhaust gas chamber decreases as the load decreases, but the pressure in the pressure gas chamber increases by switching the adjusting valve 13 at a predetermined load, and the exhaust gas chamber accordingly increases. The volume decreases as shown by the broken line.

As a result, the fuel consumption rate also changes as shown by the broken line B and becomes smaller than that of the conventional one shown by the solid line A. However, if the load is equal to or greater than the predetermined value, the pressure inside the pressure gas chamber becomes zero, and the volume of the exhaust gas chamber becomes the same as the conventional one shown by the solid line. Therefore, the fuel consumption rate is the same as the conventional one shown by the solid line A. Become.

[0022]

According to the present invention, the utilization rate of the dynamic pressure energy is increased by reducing the volume of the exhaust gas chamber when the engine load is low, and as a result, good combustion is obtained and the fuel consumption rate is improved. Can be kept low.

Further, since the volume of the exhaust gas chamber is increased at the time of high load, the pressure fluctuation of the exhaust gas is suppressed and the utilization rate of the static pressure energy is increased.
Increased charge, good combustion and low fuel consumption. As described above, good combustion can be obtained in the entire operating range of the engine, and the fuel consumption rate can be reduced.

[Brief description of drawings]

FIG. 1 shows an exhaust system for a static pressure supercharged internal combustion engine according to an embodiment of the present invention, where (A) is a system diagram and (B) is BB of (A).
It is sectional drawing which follows the line.

FIG. 2 is a diagram showing characteristics of the engine.

FIG. 3 is a system diagram showing an exhaust system of a conventional static pressure supercharged internal combustion engine.

FIG. 4 is a diagram showing a relationship between an engine output level and an exhaust energy ratio of the engine.

[Explanation of symbols]

 1 Cylinder 2 Air Supply Chamber 30 Exhaust Pipe 31 Exhaust Gas Chamber 32 Pressure Gas Chamber 10 Supercharger 11 Flexible Membrane 12 Pressure Gas Passage 13 Control Valve 14 Exhaust Pipe

Claims (1)

[Claims] 1. An exhaust system for a static pressure supercharged internal combustion engine, wherein exhaust gas from a cylinder is temporarily stored in a large-capacity exhaust pipe and then guided to a supercharger to drive the exhaust gas. The exhaust gas chamber and the pressure gas chamber are partitioned by a flexible film, the exhaust gas chamber is communicated with the cylinder and the supercharger, and the pressure gas chamber is connected to a pressure gas supply source via a regulating valve. An exhaust system for a static pressure supercharged internal combustion engine.