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.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to an improved muffler for use with a motor vehicle, such as an automobile, truck, motorcycle, boat and the like. In particular, the improved muffler has an adjustable butterfly valve positioned therewithin so as to be rotatable between open and closed positions by the operator while the vehicle is in motion in order to selectively control the exhaust flow characteristics through the muffler, the corresponding sound generated by the muffler, and the performance of the engine to which the muffler is coupled.[0003]2. Background Art[0004]Virtually all engines that are manufactured today are coupled to a muffler so as to reduce the generation of sound as engine gases are exhausted to the atmosphere. For many motor vehicles, it is often possible to substitute a new muffler for the original stock muffler. Such a substitute muffler, which may be sold by the original manufacturer or as an after market pro...

AI Technical Summary

Benefits of technology

[0010]The sound attenuating butterfly valve is preferably a disc-shaped baffle which may include a number of holes formed therein. According to a first preferred embodiment, the butterfly valve is attached to one end of an elongated motor shaft which extends through the outer body and inner liner of the muffler, such that the butterfly valve is rotatable within and relative to the inner liner. In this case, the muffler is attached to an automobile. In a fully closed position, the butterfly valve extends across and blocks the inner liner, whereby the exhaust flow therethrough is diverted through the perforated inner liner and the sound level (in decibels) emitted by the muffler is minimized. In the fully open position, the butterfly valve is rotated 90 degrees so that the exhaust flow is unrestricted and the sound level emitted by the muffler is now maximized. To accomplish the foregoing, the butterfly valve is located at a particular position within the inner liner close to the outlet end of the muffler. While the precise location of the butterfly valve will depend upon the size and the shape of the muffler and the type of engine to which the muffler is coupled, it has been found that horsepower can be increased, the engine can be made to run cooler, and fuel economy improved when the butterfly valve is located within the inner liner a distance downstream from the inlet end of the muffler which lies in a range of distances between 60%-90% of the length of the outer muffler body.

Problems solved by technology

However, locating a baffle adjacent the inlet end of the muffler has proved to be inefficient with respect to the ability to increase horsepower, to enable the engine to run cooler, and to improve fuel mileage.

What is even more, the conventional baffle is not adjustable while the motor vehicle is in motion.

Consequently, the operator is undesirably required to disassemble the muffler so as to gain access to and make internal changes to the orientation of the baffle.

Such a process of dismounting, disassembly and remounting can consume a large amount of time and result in errors by those who are not sufficiently skilled mechanics.

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