JPH0640905Y2 - Internal combustion engine muffler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a muffler used for an exhaust system of an internal combustion engine (hereinafter also referred to as an engine) mounted on a vehicle such as an automobile.

[Prior Art] Conventionally, a muffler of an engine has a bypass pipe having an opening / closing valve disposed inside or outside a side wall of an outer shell of the muffler, and an inlet of the bypass pipe intersects a flow of exhaust gas in the muffler. Since it is open in the direction, even if the open / close valve is opened, it is difficult to bypass the exhaust gas and the effect of lowering the back pressure of the exhaust gas is small.

In addition, since the vehicle tires are generally located near the side of the muffler, the pebbles and water splashed by the tires are likely to hit the mechanism part of the opening / closing valve provided in the bypass pipe, and the valve will be damaged. It was very dangerous.

As prior art materials of the present application, there are Japanese Utility Model Publication 58-98413, Japanese Utility Model Publication 59-123622 and Japanese Utility Model Publication 60-95112.

[Problems to be Solved by the Invention] This invention efficiently exhausts exhaust gas discharged from an inlet pipe into a bypass pipe in a muffler, greatly reduces the back pressure of the exhaust gas, and an on-off valve provided in the bypass pipe. The problem is to provide an engine muffler that will not be damaged by pebbles and water splashed from the tire.

[Technical Means for Solving the Problems] In order to solve the above problems, the present invention relates to a muffler of an internal combustion engine having an exhaust gas inlet pipe, an outlet pipe, and a bypass pipe, in which one end of the bypass pipe is located inside the muffler. Arranged substantially coaxially with the inlet pipe, the downstream end opening surface of the inlet pipe and the upstream end opening surface of one end of the bus pass pipe are opposed to each other, and a part of the bypass pipe is arranged on the rear outer side of the muffler. In addition, a valve is provided to open and close the bypass pipe according to the operating state of the internal combustion engine.

[Operation] With the above configuration, the bypass pipe efficiently sucks the exhaust gas discharged from the inlet pipe and discharges it to the outside of the muffler through the outlet pipe with a small flow resistance, so that the back pressure of the exhaust gas is greatly reduced. Further, since the open / close valve is located on the outer side of the rear of the muffler, it is not damaged by pebbles splashed from the tire or water.

[Embodiment] The present invention will be described below with reference to the drawings illustrating an embodiment. First
The figure shows a first embodiment. In the figure, the muffler 10 is surrounded by a cylindrical outer shell 11, a front outer plate 12 and a rear outer plate 13 that close the front and rear ends thereof. In the outer shell 11, the first separator (punching separator) 14, in the order described from the front (left in FIG. 1),
A second separator 15 and a third separator 16 are provided, and these separators and the front outer plate 12 and the rear outer plate 13 are arranged in order from the front in the fourth expansion chamber 2
The muffler 10 is divided into 0, a third expansion chamber 19, a second expansion chamber 18, and a first expansion chamber 17. The inlet pipe 21 includes a front outer plate 12, first, second and third separators 14, 15,
It is supported by 16, its front end is connected to an exhaust pipe (not shown), and its rear end faces the first expansion chamber 17. The outlet pipe 22 is supported by the first, second and third separators 14, 15, 16 and the rear outer plate 13, its front end faces the fourth expansion chamber 20, and its rear end is open to the atmosphere. An inner pipe 23 that connects the second and third expansion chambers 18 and 19 is attached to the second separator 15. The bypass pipe 24 is L-shaped and is composed of a long leg portion 24a, a short leg portion 24b, and a bent portion 24c connected to the free ends of the short leg portions 24b and substantially parallel to the long leg portion 24a. The long leg portion 24a is supported by the second and third separators 15 and 16 and the rear outer plate 13, the short leg portion 24b is located outside the rear of the muffler 10 and is substantially parallel to the rear outer plate 13, and the bent portion 24c is the rear portion. It penetrates the outer plate 13 and extends into the first expansion chamber 17, and is almost on the axis of the inlet pipe 21. Therefore, the front end opening surface of the bent portion 24c faces the rear end opening surface of the inlet pipe 21. Also long leg 24a
The open end of is facing the third expansion chamber 19. An opening / closing valve 25 is attached to the short leg portion 24b, and the valve 25 is a sensor connected to various sensors such as a water temperature sensor and an engine speed sensor for detecting an engine operating state.
The bypass pipe 24 is opened and closed by an actuator 27 that operates according to a command from 26.

In the above structure, part of the exhaust gas flowing into the inlet pipe 21 enters the second expansion chamber 18 through the through hole 21a, and further passes through the inner pipe 23, the third expansion chamber 19, and the first separator 14 having the punch holes. It enters the fourth expansion chamber 20, and then is discharged to the outside of the muffler 10 through the outlet pipe 22.
This produces a silencing effect. The remaining exhaust gas smoothly enters the bent portion 24c because the front end opening surface of the bent portion 24c of the bypass pipe 24 substantially coaxially faces the rear end opening surface of the inlet pipe 21. When the opening / closing valve 25 is open, the exhaust gas enters the third expansion chamber 19 through the short leg portion 24b and the long leg portion 24a of the bypass pipe 24, and further the first separator 14, the fourth extension chamber 20, and the outlet pipe 22. After that, it is smoothly discharged to the outside of the muffler 10. At this time, the flow resistance of the exhaust gas is small. For this reason, the back pressure of the exhaust gas is reduced, so that the engine output can be prevented from being reduced by the back pressure. Further, since the opening / closing valve 25 is arranged on the outer rear side of the muffler 10, it is prevented from being damaged by being directly hit by pebbles and water splashed by the tire. Further bypass pipe 24
Since the outer shell 11 is not perforated when it is mounted, the muffler has a high strength, the productivity and the assemblability are improved, and the production cost is reduced.

FIG. 2 shows the muffler 30 of the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the figure, the bypass pipe 34 is formed in an almost L shape, and has long leg portions 34a, short leg portions 34b, first bent portions 34c, and second leg portions 34c.
It is composed of a bent portion 34d. The first bent portion 34c extends through the rear outer plate 13 into the first expansion chamber 17, is substantially parallel to the long leg portion 34a, and is positioned substantially coaxial with the inlet pipe 21, and the front end opening surface thereof is the inlet. It faces the rear end opening surface of the pipe 21. The second bent portion 34d is substantially parallel to the short leg portion 34b, penetrates the outer shell 11 and extends into the third expansion chamber 19. The long leg portion 34a is located on the lateral side of the muffler 30, and the short leg portion 34b is located on the rear outer side of the muffler 30.
The open / close valve 25 is attached to the short leg portion 34b.

[Effect] Since the present invention has the above configuration, it has the following excellent effects.

(A) Since the inlet pipe and one end of the bypass pipe are arranged substantially coaxially in the muffler, and the downstream end opening surface of the inlet pipe and the upstream end opening surface of the one end of the bypass pipe are opposed to each other, the opening / closing valve is opened. At this time, the exhaust gas flowing out of the inlet pipe smoothly flows into the bypass pipe and is discharged from the muffler through the outlet pipe to the outside of the muffler, but the flow resistance acting on the exhaust gas at this time is small. Therefore, the back pressure of the exhaust gas is reduced, and the engine output is prevented from being reduced.

(B) Since the open / close valve is arranged outside the muffler, the open / close valve is not damaged by pebbles and water splashed by the tires of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a plan view of a first embodiment. FIG. 2 shows a plan view of the second embodiment. 10,30 …… Muffler 21 …… Inlet pipe 22 …… Outlet pipe 24 …… Bypass pipe 25 …… Open / close valve 34 …… Bypass pipe

Claims (1)

[Scope of utility model registration request] 1. A muffler for an internal combustion engine having an exhaust gas inlet pipe, an outlet pipe, and a bypass pipe, wherein one end of the bypass pipe is arranged in the muffler substantially coaxially with the inlet pipe, and the downstream end of the inlet pipe. The opening surface and the upstream end opening surface of the one end of the bus pass pipe are opposed to each other, and a part of the bypass pipe is arranged outside the rear of the muffler, and the bypass pipe is opened and closed in this part according to the operating state of the internal combustion engine A muffler for an internal combustion engine, which is provided with a valve.