Muffler for internal combustion engine

• US 5,801,343 A
• Filed: 06/16/1995
• Issued: 09/01/1998
• Est. Priority Date: 11/09/1993
• Status: Expired due to Term

• Current Assignee: Futaba Industrial Company Limited
• Original Assignee: Futaba Industrial Company Limited
• Inventors: Fujiwara, Kunihiko, Ohno, Kazunari, Kato, Tetsuo, Morishita, Takanori, Suzuki, Mitsuro
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US08/481,445
• Time in Patent Office: 1,173 Days
• Field of Search: 181/237, 181/241, 181/253, 181/254, 181/265, 181/266, 181/272, 181/277, 181/278, 181/211
• US Class Current: 181/254
• CPC Class Codes: F01N 1/02 by using resonance
• CPC Class Codes: F01N 1/084 the gases flowing through the silencer two or more times longitudinally in opposite directions, e.g. using parallel or concentric tubes
• CPC Class Codes: F01N 1/089 using two or more expansion chambers in series F01N1/083, F01N1/084, F01N1/086 take precedence
• CPC Class Codes: F01N 1/165 for adjusting flow area
• CPC Class Codes: F01N 1/166 for changing gas flow path through the silencer or for adjusting the dimensions of a chamber or a pipe F01N1/165 takes precedence
• CPC Class Codes: F01N 13/085 having means preventing foreign matter from entering exhaust conduit
• CPC Class Codes: F01N 2290/10 actuated by pressure of exhaust gases, e.g. exhaust pulses
• CPC Class Codes: F01N 2490/155 being disposed one after the other in flow direction

Abstract

In a muffler for an internal combustion engine which is provided with a valve capable of closing and opening an open end of a by-pass inner pipe, the opening and closing operation of the valve is performed by means of 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 proximate 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 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.

Claims

1. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional 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;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of and proximate the by-pass port, the flap valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port reaches a desired pressure;

wherein a buffer material is interposed between the flap valve and a stay supporting the shaft.

2. A muffler according to claim 1, wherein the by-pass port is defined by a by-pass pipe through the partitioning wall, the flap valve engages an open end of the by-pass pipoe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.

3. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional exhaust gas path extending from the first to the second chamber to permit exhaust gas to flow room the inlet pipe to the outlet pipe;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of and proximate the by-pass port, the flap valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port reaches a desired pressure;

wherein the resilient member is a coil spring helically wound about the shaft.

4. A muffler according to claim 3, wherein the by-pass port is defined by a by-pass pipe passing through the partitioning wall the flap valve engages an open end of the by-pass pipe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.

5. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional 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;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of an proximate the by-pass port, the flat valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port reaches a desired pressure;

wherein the resilient member is disposed entirely within the housing proximate the by-pass port and a buffer material is interposed between the flap valve and a stay supporting the shaft.

6. A muffler according to claim 5, wherein the by-pass port is defined by a by-pass pipe passing through the partitioning wall, the flap valve engages an open end of the by-pass pipe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.

7. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional 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;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of an proximate the by-pass port, the flap valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port reaches a desired pressure;

wherein the resilient member is disposed entirely within the housing proximate the by-pass port and is a coil spring helically wound about the shaft.

8. A muffler according to claim 7, wherein the by-pass port is defined by a by-pass pipe passing through the partitioning wall the flap valve engages an open end of the by-pass pipe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.

9. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional 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;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of and proximate the by-pass port, the flat valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port 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.

10. A muffler according to claim 9, wherein the by-pass port is defined by a by-pass pipe passing through the partitioning wall, the flap valve enrages an open end of the by-pass pipe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.

11. 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 having an inlet in 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) a by-pass port extending through the partitioning wall separating the first and second chambers to provide an additional 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;

f) a flap valve, provided at the by-pass port and supported on a shaft displaced laterally of an proximate the by-pass port, the flap valve being movable between a position at which the flap valve closes the by-pass port and a position at which the flap valve allows exhaust gas to flow through the by-pass port; and

g) a resilient member positioned and supported proximate the flap valve to resiliently bias the flap valve to the position at which the by-pass port is closed while permitting exhaust gas in the by-pass port to move the flap valve against the resilient bias to allow exhaust gas to flow through the by-pass port when the exhaust gas in the by-pass port reaches a desired pressure;

wherein the resilient member is composed of Inconel and is a coil spring helically wound about the shaft.

12. A muffler according to claim 11, wherein the by-pass port is defined by a by-pass pipe passing through the partitioning wall the flap valve engages an open end of the by-pass pipe and a shock absorbing material is interposed between the flap valve and the open end of the by-pass pipe.