JPH0625629Y2 - Silencer for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a silencer for an internal combustion engine.

[Prior art]

Conventionally, as a silencer for an internal combustion engine, two outlet pipes 1 and 2 are provided as shown in FIG.
The on-off valve 3 is installed inside, and when the engine is running at low speed and low load, the shut-off valve 3 is closed by emphasizing the sound deadening effect rather than the back pressure. There is a type in which the opening / closing valve 3 is opened with emphasis on the reduction effect.

[Problems to be solved by the present invention]

In the above-mentioned conventional structure, when the opening / closing valve 3 is closed, exhaust gas is not discharged from the outlet pipe 2 having the opening / closing valve 3, so that there is a problem that the appearance is deteriorated. In addition, there is a problem that it cannot be applied to the one outlet pipe.

Then, this invention aims at proposing the silencer which can eliminate the said problem and can exhibit the noise reduction and back pressure reduction effect corresponding to the rotation state of the said engine in one or two outlet pipes. is there.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention divides the interior of the chamber into a plurality of chambers, and an inlet pipe is formed so as to penetrate the downstream side chamber so that its exhaust port opens to the upstream side chamber,
A communication hole is formed in the inlet pipe in the chamber downstream of the upstream chamber in which the exhaust port is opened, and the outlet pipe of the outlet pipe is opened to the upstream chamber, and the downstream portion thereof passes through each chamber to the outside of the unit. Is installed so as to open in the chamber, a communication hole is formed in the outlet pipe in a chamber downstream of the chamber in which the communication hole of the inlet pipe is located, and
An opening / closing valve for opening / closing the flow passage is provided in the outlet pipe upstream of the communication hole of the outlet pipe.

[Action]

When the opening / closing valve 17 is closed at low engine speed and low load, the exhaust gas from the inlet pipe 10 passes through each chamber through the communication hole without being discharged directly through the outlet pipe 13. It flows out. Further, when the opening / closing valve 17 is opened during high engine speed or high load, the main flow of exhaust gas from the inlet pipe 10 directly flows out through the outlet pipe 13.

〔Example〕

 Next, an embodiment of the present invention shown in FIG. 1 will be described.

4 is the outer shell of the muffler, the inside of which is the
It is divided into a chamber 7, a second chamber 8 and a third chamber 9. Reference numeral 10 denotes an inlet pipe, the exhaust port 11 of which is opened to the first chamber 7, and a communication hole 12 is formed in the peripheral wall located in the second chamber 8. Reference numeral 13 denotes an outlet pipe, the exhaust introduction port 14 of which is opened to the first chamber 7, the downstream portion thereof is bent in a U shape, and the bent portion 15 projects out of the device, and further the downstream portion thereof is inside the silencer. The exhaust port 16 penetrates through and opens outside the device. An opening / closing valve 17 for opening / closing the flow passage is installed in the bent portion 15. The opening / closing valve 17 is operated by a drive device (not shown) so as to be closed when the engine is rotating at low speed and low load, and is opened when the engine is rotating at high speed and high load. A communication hole 18 is formed in the peripheral wall located in the third chamber 9 part. 19 is the second chamber 8
And the third chamber 9 is an inner pipe that communicates with the third chamber 9.

In this embodiment, when the opening / closing valve 17 is closed during low engine speed and low load, the exhaust port of the inlet pipe 10
The first chamber 7 having the opening 11 is blocked from communicating with the outside via the outlet pipe 13, and the inlet pipe 10
Exhaust gas flows out from the communication hole 12, passes through the second chamber 8, the inner pipe 19, and the third chamber 9 into the outlet pipe 13 through the communication hole 18, and flows out of the device through the exhaust port 16. . Therefore, the first chamber 7 becomes the resonance chamber, and the second chamber 8 and the third chamber 9 become the expansion chambers, and the sound deadening effect is enhanced.

Next, when the opening / closing valve 17 is opened at the time of high rotation and high load of the engine, the main flow of the exhaust gas from the inlet pipe 10 is discharged from the first chamber 7 through the outlet pipe 13 together with the outflow. . Therefore, the silencing effect is less than the above, but the back pressure reducing effect is higher.

In the outlet pipe of the above-mentioned embodiment, the bent portion 15 may be located inside the vessel as shown in FIG. 2, and as shown in FIG. The exhaust port 16 may be taken out from the front wall of the outer shell, passed through the outer portion of the outer shell 4 and put into the container from the rear wall, and the exhaust port 16 may be opened to the outside of the device after penetrating the inside of the device.

Figure 4 shows two pipes in the wake of the outlet pipe 13.
It is branched into 13a and 13b.

[Effect of device]

As described above, according to the present invention, at the time of low engine speed and low load, exhaust gas from the inlet pipe can flow into each expansion chamber and resonance chamber to enhance the sound deadening effect. When the load is high, the main flow of the exhaust gas from the inlet pipe can be directly flowed out of the outlet pipe to enhance the back pressure reducing effect. Moreover, the above effect can be exhibited by one outlet pipe, and by branching the rear end portion of the outlet pipe into two, exhaust gas always flows out in equal amounts from the two branch pipes, which is attractive. Also gets better.

[Brief description of drawings]

1 to 4 are side sectional views showing four embodiments of the present invention, and FIG. 5 is a side sectional view showing a conventional structure. 7,8,9 ... Room, 10 ... Inlet pipe, 11 ... Exhaust port, 12,18 ... Communication hole, 13 ... Outlet pipe,
14 ... Exhaust inlet, 17 ... Open / close valve

Claims (1)

[Scope of utility model registration request] 1. A chamber in which the inside of the chamber is divided into a plurality of chambers, and an inlet pipe penetrates a downstream chamber so that an exhaust port thereof opens to an upstream chamber, the downstream of the upstream chamber in which the exhaust port opens. In the chamber of (1), a communication hole is formed in the inlet pipe, and the outlet pipe is installed so that its exhaust introduction port opens to the upstream chamber and its downstream portion opens outside the chamber through each chamber. A communication hole is formed in the outlet pipe in a chamber downstream of the chamber in which the communication hole is located, and an opening / closing valve for opening and closing the flow passage is provided in the outlet pipe upstream of the communication hole of the outlet pipe. A silencer for an internal combustion engine, which is characterized in that