US 5,971,098 AGranted

Muffler for internal combustion engine

AssigneeFutaba Industrial Co., Ltd.

InventorsMitsuro Suzuki, Kazunari Ohno, Kunihiko Fujiwara, Tetsuo Kato, Takanori Morishita

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Abstract

In a muffler for internal combustion engine which is provided with a valve capable of closing and opening an open end of by-pass inner pipe, the opening and closing operation of the valve is performed via the exhaust gas pressure, without being affected by external factors. Also, the structure is simple and easy to be assembled. On a fixed shaft (36) supported in the vicinity of an open end (28a) of a by-pass inner pipe (28) is a valve (32) rotatably mounted. The valve (32) is urged against the open end (28a) by a coil spring (42), and when fitted in a flange part (38), it closes the open end (28a). When the revolving speed of the internal combustion engine is low, the pressure inside the by-pass inner pipe (28) is smaller than the operative force which is an addition of the urging force by the coil spring (42) and the external pressure. The open end (28a) is therefore closed. On the other hand, when the revolving speed rises and the pressure has increased to a predetermined pressure, their relation is reversed. Specifically, the valve retracts from the open end (28a) thereby placing the by-pass inner pipe (28) in a communicated condition.

Claims15

Dependent claims

A muffler for an internal combustion engine, comprising:

a) a housing having a plurality of separate chambers, each of said chambers being separated from said other chambers by a partitioning wall;
b) an inlet pipe communicating with a first of the chambers for introducing exhaust gas to the first chamber;
c) an outlet pipe communicating with a second of the chambers for exhausting gas from the muffler;
d) a port in the partitioning wall separating the first and second chambers to provide an exhaust gas path extending from the first to the second chamber to permit exhaust gas to flow from the inlet pipe to the outlet pipe;
e) at least one second port in the partitioning wall separating the first and a third chamber to permit exhaust gas to flow between the first and third chambers;
f) a by-pass pipe providing an exhaust gas path extending from the third to the second chamber to permit exhaust gas to flow from the third chamber to the outlet pipe;
g) a flap valve, provided at an open downstream end of the by-pass pipe and supported on a shaft displaced laterally of and proximate the open end, the flap valve being movable between a position at which the flap valve closes the downstream open end and a position at which the flap valve allows exhaust gas to flow through the by-pass pipe;
and
h) a resilient member positioned and supported proximate the flap valve to resiliently bias the valve to the position at which the open end is closed while permitting exhaust gas in the by-pass pipe to move the valve against the resilient bias to allow exhaust gas to flow through the by-pass pipe when the exhaust gas in the by-pass pipe reaches a desired pressure;
wherein a buffer material is interposed between the flap valve and a stay supporting the shaft.

7 more elements

A muffler for an internal combustion engine, comprising:

a) a housing having a plurality of separate chambers, each of said chambers being separated from said other chambers by a partitioning wall;
b) an inlet pipe communicating with a first of the chambers for introducing exhaust gas to the first chamber;
c) an outlet pipe communicating with a second of the chambers for exhausting gas from the muffler;
d) a port in the partitioning wall separating the first and second chambers to provide an exhaust gas path extending from the first to the second chamber to permit exhaust gas to flow from the inlet pipe to the outlet pipe;
e) at least one second port in the partitioning wall separating the first and a third chamber to permit exhaust gas to flow between the first and third chambers;
f) a by-pass pipe providing an exhaust gas path extending from the third to the second chamber to permit exhaust gas to flow from the third chamber to the outlet pipe;
g) a flap valve, provided at the open downstream end of the by-pass pipe and supported on a shaft displaced laterally of and proximate the open downstream end, the flap valve being movable between a position at which the flap valve closes the by-pass pipe and a position at which the flap valve allows exhaust gas to flow through the by-pass pipe;
and
h) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass pipe is closed while permitting exhaust gas in the by-pass pipe to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass pipe when the exhaust gas in the by-pass pipe reaches a desired pressure;
wherein a buffer material is interposed between the flap valve and a stay supporting the shaft and the resilient member is disposed entirely within the second chamber proximate the open downstream end.

7 more elements

A muffler for an internal combustion engine, comprising:

a) a housing having a plurality of separate chambers, each of said chambers being separated from said other chambers by a partitioning wall;
b) an inlet pipe communicating with a first of the chambers for introducing exhaust gas to the first chamber;
c) an outlet pipe communicating with a second of the chambers for exhausting gas from the muffler;
d) a port in the partitioning wall separating the first and second chambers to provide an exhaust gas path extending from the first to the second chamber to permit exhaust gas to flow from the inlet pipe to the outlet pipe;
e) at least one second port in the partitioning wall separating the first and a third chamber to permit exhaust gas to flow between the first and third chambers;
f) a by-pass pipe providing an exhaust gas path extending from the third to the second chamber to permit exhaust gas to flow from the third chamber to the outlet pipe;
g) a flap valve, provided at an open downstream end of the by-pass pipe, and supported on a shaft displaced laterally of and proximate said open downstream end, the flap valve being movable between a position at which the valve closes the by-pass pipe and a position at which the valve allows exhaust gas to flow through the by-pass pipe;
and
h) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass pipe is closed while permitting exhaust gas in the by-pass pipe to move the valve against the resilient bias to allow exhaust gas to flow through the by-pass pipe when the exhaust gas in the by-pass pipe reaches a desired pressure;
wherein the resilient member is composed of Inconel and a buffer material is interposed between the flap valve and a stay supporting the shaft.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/000,888Filed 30 Dec 1997 · division
Priority: JP 5-2794799 Nov 1993
Granted: 26 Oct 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

F01N 13/085
Other arrangements or adaptations of exhaust conduits: having means preventing foreign matter from entering exhaust conduit
F01N 1/02
Silencing apparatus characterised by method of silencing: by using resonance
F01N 1/084
By reducing exhaust energy by throttling or whirling: the exhaust gases flowing through the silencer two or more times longitudinally in opposite…
F01N 1/089
By reducing exhaust energy by throttling or whirling: using two or more expansion chambers in series