JPH036007B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a silencer for a vehicle, primarily an automobile engine.

(2) Prior Art Conventionally, the one shown in FIG. 3 has been known as a vehicle silencer. In this one, a silencer 02 is disposed laterally on one side of the rear part of the vehicle body 01, and the silencer 0
An upstream exhaust pipe 05 connected to the engine E' and a downstream exhaust pipe 07 opening to the atmosphere are connected to opposing end surfaces of the engine E'.

(3) Problems to be Solved by the Invention By the way, the low frequency limit frequency o that generally determines the silencing performance of an expansion chamber is given by the following equation.

Here, C, π: Constant, S: Cross-sectional area of the exhaust pipe downstream from the expansion chamber, V: Volume of the expansion chamber, l: Length of the exhaust pipe downstream from the expansion chamber By the way, the low frequency limit frequency of noise reduction performance o The smaller is, the better the silencing performance is.In order to reduce o, as is clear from the above equation, it is conceivable to make S smaller and V or l larger. However, if S is made small, the back pressure resistance of the engine increases, causing a reduction in its output, and if V is made large, the muffler itself becomes large, which not only limits the installation space but also increases cost. Furthermore, if l was simply increased, the distance between the front and rear ends of the exhaust pipe would increase, and there would be a limit to how it could be placed in the limited space under the car body, and furthermore, it would be difficult to fit a long exhaust pipe into the car body. Since the long exhaust pipe is supported, vibrations of the long exhaust pipe are transmitted to the vehicle body, resulting in a problem of increased vehicle body vibration.

The present invention was made in view of the above circumstances, and by specifying the arrangement of the silencer and the connection position of the exhaust system connected to it, and further reducing the support points of the upper and downstream exhaust pipes to the vehicle body, To provide a noise reduction device for an engine in a vehicle with a simple configuration, which allows the length l to be set long without causing the problems described above, and greatly improves noise reduction performance and reduces vehicle body vibration. The purpose is to

B. Structure of the Invention (1) Means for Solving Problems According to the present invention, in order to achieve the above object, an upstream exhaust pipe connected to an engine mounted on a vehicle body is connected to an exhaust pipe of a silencer elastically supported by the vehicle body. Connect to the inlet,
In a vehicle engine muffler, the muffler has a downstream exhaust pipe opened to the atmosphere connected to an exhaust inlet of the muffler, and the muffler is biased toward one side of the rear of the vehicle body, and The muffler is arranged so that its axis runs along the width direction of the vehicle body, and an exhaust inlet and an exhaust outlet to which the upstream and downstream exhaust pipes are connected are both opened at one end surface of the muffler near the center of the vehicle body. The downstream exhaust pipe is extended in the width direction of the vehicle body, and the upstream exhaust pipe and downstream exhaust pipe, which are parallel to each other, are integrally connected by a rigid connecting body.

(2) Effects According to the above configuration, the exhaust silencing effect is greatly enhanced by the long downstream exhaust pipe, and the transmission of exhaust pipe vibrations to the vehicle body is reduced.

(3) Embodiment A preferred embodiment of the present invention will be described below with reference to the drawings.

In addition, in the following explanation, front, rear, left, right, top, and bottom refer to the direction of travel of the vehicle (arrow direction in Figure 1).
I say to.

The engine E is mounted horizontally in the front central part of the vehicle body 1, that is, the crank axis L-L is substantially perpendicular to the direction of travel of the vehicle, while the silencer 2 is mounted on the rear left side of the vehicle body 1. The elastic support 12 is provided on the vehicle body 1 so that the width direction of the vehicle body 1, that is, the longitudinal axis LL thereof is substantially parallel to the crank axis LL.

An exhaust manifold 4 is connected to the rear surface of the engine body 3 of the engine E.
The inlet of the engine body 1 is communicated with an exhaust port opened in the engine body 1. A front end of an upstream exhaust pipe 5 is connected to the rear end of the exhaust manifold 4 . This upstream exhaust pipe 5 extends along the longitudinal direction of the vehicle body and is elastically supported 13 by the vehicle body, and a pre-chamber 6 for auxiliary noise reduction is interposed in the middle thereof. The rear half of the upstream exhaust pipe 5 is curved so as to bypass a fuel tank 8 supported by the vehicle body 1, and then extends in the width direction of the vehicle body 1 toward the muffler 2.

One end surface 2a of the muffler 2 near the center of the vehicle body 1
, an exhaust inlet 9 and an exhaust outlet 10 are both opened, and a downstream exhaust pipe 5a of the upstream exhaust pipe 5 extending in the width direction of the vehicle body 1 is connected to the exhaust inlet 9.
is connected to the exhaust outlet 10, and the front end of the downstream exhaust pipe 7 is connected to the exhaust outlet 10. This downstream exhaust pipe 7 is substantially parallel to the downstream end portion 5a of the upstream exhaust pipe 5, and extends long to the right along the width direction of the vehicle body 1, and its rear end is bent toward the rear. It is opened to the atmosphere.

As clearly shown in FIG. 2, the downstream end portion 5a of the upstream exhaust pipe 5 and the downstream exhaust pipe 7 are approximately parallel to each other, and their intermediate portions are integrally connected by a rigid connector 11. The downstream exhaust pipe 7 is connected to the vehicle body 1.
is not supported.

This elastic connecting body 11 is made of a metal plate such as an iron plate, and its longitudinal direction (direction of arrow a in FIGS. 2 and 3)
and has high rigidity in the width direction (direction of arrow b in Figure 3). Therefore, the longitudinal and vertical vibrations of the downstream end portion 5a of the upstream exhaust pipe 5 and the downstream exhaust pipe 7 are mutually canceled and damped by the rigid connecting body 11, and the vibrations are transmitted to the vehicle body. is reduced as much as possible. Further, the rigid connecting body 11 is configured to have some flexibility in its thickness direction (arrow c direction in FIG. 2), and has some flexibility in the length direction of the upstream exhaust pipe 5 and the downstream exhaust pipe 7. It is designed to absorb relative expansion and contraction due to heat.

Next, the operation of the embodiment of the present invention will be explained.

The exhaust gas generated by the operation of engine E now is
It flows from the exhaust manifold 4 through the upstream exhaust pipe 5 and is supplementally muffled by a pre-chamber 6 interposed in the middle of the pipe 5, and then flows into the muffler 2, where it is muffled, and then passed through the downstream exhaust pipe 7. is released into the atmosphere through

By the way, the muffler 2 is elastically supported 12 on the rear left side of the vehicle body 1 so that its longitudinal axis l-l runs along the width direction of the vehicle body 1. By connecting both the side exhaust pipes 5 and 7, the length of the downstream side exhaust pipe 7 can be made sufficiently long, and the above-mentioned low frequency limit frequency can be achieved.
o can be made small, and the noise reduction performance is improved.

Furthermore, since the parallel parts of the upstream exhaust pipe 5 and the downstream exhaust pipe 7 are integrally connected by the rigid connecting body 11, the longitudinal and vertical vibrations of each of the exhaust pipes 5 and 7 are suppressed by the rigid connection. The vibrations are transmitted to each other through the body 11 and cancel each other out, so that the vibrations are effectively damped. Therefore, even if the upstream and downstream exhaust pipes 5 and 7 are formed to be long as described above, their longitudinal and vertical vibrations will not become large.
Furthermore, since the downstream exhaust pipe 7 is not supported by the vehicle body 1, vehicle body vibrations caused by vibrations of the exhaust pipes 5 and 7 are significantly reduced.

In addition, the upstream and downstream exhaust pipe systems 5, 7
repeats expansion and contraction in their longitudinal direction by heating and cooling, but the expansion and contraction is absorbed by the flexibility of the rigid connecting body 11 in the thickness direction.

C. Effects of the Invention As is clear from the above embodiments, according to the present invention, the muffler is biased toward one side of the rear of the vehicle body, and is supported by the vehicle body such that its vertical axis runs along the width direction of the vehicle body, An exhaust inlet and an exhaust outlet to which upstream and downstream exhaust pipes are connected are both provided on one end surface of the muffler near the center of the vehicle body, and the downstream exhaust pipe is extended in the width direction of the vehicle body. Therefore, the length of the downstream exhaust pipe can be made as long as possible within the limited space under the vehicle body, and the above-mentioned low frequency limit frequency can be made small, making it possible to significantly improve the silencing performance.

Furthermore, since the upstream exhaust pipe and the downstream exhaust pipe are integrally connected by the rigid connecting body, the vibrations of each of the exhaust pipes are mutually canceled by the rigid connecting body, and the downstream exhaust pipe is Even if the exhaust pipe is formed to be long as described above, the vibration is attenuated as much as possible, and together with the omission of supporting the downstream exhaust pipe to the vehicle body, the transmission of the vibration to the vehicle body can be reduced.

In addition, as in the above embodiment, the rigid connection body is
By providing flexibility along the longitudinal direction of the upstream exhaust pipe and the downstream exhaust pipe, expansion and contraction in the longitudinal direction of these exhaust pipes is allowed.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the silencing device of the present invention, with Figure 1 being an overall plan view, and Figure 2 being a
FIG. 3 is an enlarged view of part A in the figure, FIG. 3 is a view taken along the line shown in FIG. 2, and FIG. 4 is an overall plan view of a conventional silencer. E... Engine, 1... Vehicle body, 2... Silencer,
5... Upstream exhaust pipe, 9... Exhaust inlet, 10...
...Exhaust outlet, 11...Rigid connection.

Claims (1)

[Claims] 1. An upstream exhaust pipe connected to an engine mounted on a vehicle body is connected to an exhaust inlet of a silencer elastically supported by the vehicle body, and an exhaust pipe is connected to an exhaust outlet of the silencer that is open to the atmosphere. In a vehicle engine muffling device, the muffler is biased toward one rear side of the vehicle body, and the vertical axis thereof is arranged along the width direction of the vehicle body, An exhaust inlet and an exhaust outlet to which the upstream and downstream exhaust pipes are connected are both opened at one end surface of the muffler near the center of the vehicle body, and the downstream exhaust pipe is extended in the width direction of the vehicle body. 1. A silencer for an engine in a vehicle, characterized in that an upstream exhaust pipe and a downstream exhaust pipe that are parallel to each other are integrally connected by a rigid connector. 2. In the engine silencer for a vehicle according to claim 1, the rigid connecting body has flexibility that allows relative movement in the axial direction of the upstream exhaust pipe and the downstream exhaust pipe. A silencer for the engine in a vehicle.