Muffler having adjustable butterfly valve for improved sound attenuation and engine performance

Abstract

A muffler to be coupled to the engine of a motor vehicle (e.g., a car, truck, motor cycle, boat, and the like) so that exhaust gases emitted by the engine can be exhausted to the atmosphere. The muffler includes an outer cylindrical body and an inner cylindrical liner having a plurality of apertures formed therethrough. Sound absorbing packing material is located in an annular space between the outer body and the inner liner. An adjustable butterfly valve is located within the inner liner and rotatable between open and closed positions to control the gas flow through the liner, the sound generated by the muffler as a result thereof, and the performance of the engine to which the muffler is coupled. The rotation of the butterfly valve is controlled by an external DC motor or a continuous cable. The shaft of the motor or the cable is connected through the outer body and inner liner of the muffler to the butterfly valve. By closing a manually accessible motor control switch electrically connected to the motor or by pulling on the cable, the operator of the motor vehicle has the ability to control the rotation of the butterfly valve connected to the motor shaft or the cable while the vehicle is in motion.

1 . A muffler to be coupled to the engine of a motor vehicle to receive gases therefrom to be exhausted to the atmosphere, said muffler comprising:
 a generally cylindrical outer body;   a generally cylindrical inner liner spaced radially inward from said outer body and having a plurality of apertures formed therein, said inner liner receiving the gases from the engine to be exhausted to the atmosphere;   an adjustable valve plate positioned within said inner liner and rotatable between open and closed positions;   a rotatable shaft extending through said outer body and said inner liner and connected to said adjustable valve plate to impart a rotational force to said valve plate to cause said valve plate to rotate between said open and closed positions so as to control the gas flow through said inner liner; and   means by which to enable the operator of said motor vehicle to control the rotation of said rotatable shaft and the corresponding rotational force imparted to said adjustable valve plate while the motor vehicle is in motion.   
   
   
       2 . The muffler recited in  claim 1 , wherein said means to enable the operator to control the rotation of said rotatable shaft to cause said valve plate to rotate between said open and closed positions with respect to said inner liner is a motor. 
   
   
       3 . The muffler recited in  claim 2 , wherein said motor is mounted on said muffler at a location outside the outer body of said muffler. 
   
   
       4 . The muffler recited in  claim 3 , further comprising a spacer interconnected between said motor and the outer body of said muffler, said spacer having a channel running longitudinally therethrough, and said rotatable shaft extending from said motor to the inner liner of said muffler via the channel of said spacer. 
   
   
       5 . The muffler recited in  claim 4 , wherein said spacer is manufactured from a non-heat conducting material so as to reduce the transfer of heat from the outer body of said muffler to said motor by way of said spacer. 
   
   
       6 . The muffler recited in  claim 4 , wherein said spacer has at least one vent opening formed therein through which heat transferred from the outer body of said muffler to said spacer is vented to the atmosphere and away from said motor. 
   
   
       7 . The muffler recited in  claim 2 , wherein said motor is a DC motor that is energized to cause said rotatable shaft and said valve plate connected thereto to rotate, said motor being energized by a DC current carried by an electrical power cord connected to said motor. 
   
   
       8 . The muffler recited in  claim 7 , further comprising a motor control switch connected to said electrical power cord, said motor control switch being accessible to and manipulated by the operator of the motor vehicle while the vehicle is in motion to control the energization of said DC motor and the corresponding rotation of said rotatable shaft and said valve plate connected thereto. 
   
   
       9 . The muffler recited in  claim 1 , wherein said valve plate is detachably connected to said rotatable shaft. 
   
   
       10 . The muffler recited in  claim 1 , wherein said valve plate has at least one gas transmitting hole formed therein. 
   
   
       11 . The muffler recited in  claim 1 , further comprising a layer of fiberglass located between the outer body and the inner liner of said muffler to absorb sound being transmitted thereto through the apertures formed in said inner liner. 
   
   
       12 . The muffler recited in  claim 11 , further comprising a layer of steel fibers located between the outer body and the inner liner of said muffler adjacent said fiberglass layer to absorb sound being transmitted to said layers of fiberglass and steel fibers through the apertures formed in said inner liner. 
   
   
       13 . The muffler recited in  claim 1 , wherein said valve plate is positioned within the inner liner of said muffler so as to lie at least 60% of the length of said inner liner downstream from the end of said inner liner at which the engine gases are received and closer to the opposite end of said inner liner at which the engine gases are exhausted to the atmosphere. 
   
   
       14 . A muffler to be coupled to the engine of a motor vehicle to receive gases therefrom to be exhausted to the atmosphere, said muffler comprising:
 an outer body;   an inner liner spaced inwardly from said outer body and having a plurality of apertures formed therein, said inner liner receiving the gases from the engine to be exhausted to the atmosphere;   an adjustable valve plate positioned within said inner liner and rotatable between open and closed positions;   a motor; and   a motor shaft extending from said motor and coupled to said valve plate through said outer body and said inner liner, said motor being energized to impart a rotational force to said motor shaft by which to cause said valve plate connected to said motor shaft to rotate between said open and closed positions to control the flow of engine gases through said inner liner.   
   
   
       15 . The muffler recited in  claim 14 , further comprising a motor control switch electrically connected to said motor, said motor control switch being accessible to and manipulated by the operator of the motor vehicle while the vehicle is in motion to control the energization of said motor and the corresponding rotation of said rotatable shaft and said valve plate coupled thereto. 
   
   
       16 . The muffler recited in  claim 14 , wherein said valve plate is positioned within the inner liner of said muffler so as to lie at least 60% of the length of said inner liner downstream from the end of said inner liner at which the engine gases are received and closer to the opposite end of said inner liner at which the engine gases are exhausted to the atmosphere. 
   
   
       17 . The muffler recited in  claim 14 , further comprising a sound absorbing packing material located between the outer body and the inner liner of said muffler to absorb sound transmitted thereto through the apertures formed in said inner liner. 
   
   
       18 . A muffler to be coupled to the engine of a motor vehicle to receive gases therefrom to be exhausted to the atmosphere, said muffler comprising:
 a generally cylindrical outer body;   a generally cylindrical inner liner spaced radially inward from said outer body and having a plurality of apertures formed therein, said inner liner receiving the gases from the engine to be exhausted to the atmosphere;   an adjustable valve plate positioned within said inner liner and rotatable between open and closed positions;   a rotatable pivotable rod extending through said outer body and said inner liner and connected to said adjustable valve plate to impart a rotational force to said valve plate to cause said valve plate to rotate between said open and closed positions so as to control the gas flow through said inner liner; and   a cable by which to enable the operator of said motor vehicle to control the rotation of said pivot rod and the corresponding rotational force imparted to said adjustable valve plate while the motor vehicle is in motion, an axial pulling or pushing force applied to said cable imparting a rotational force to said pivot rod for causing a rotation of said valve plate.   
   
   
       19 . The muffler recited in  claim 18 , wherein said pivot rod includes an arm that extends at an angle from said pivot rod to be coupled to said cable. 
   
   
       20 . The muffler recited in  claim 18 , further comprising a sound absorbing packing material located between the outer body and the inner liner of said muffler to absorb sound transmitted thereto through the apertures formed in said inner liner.