Compact exhaust silencer for diesel locomotives

A compact exhaust silencer for use with diesel locomotives of the type having a single elongated exhaust outlet with limited clearance space from the outlet to the locomotive body wall, said silencer comprising;

• a mounting base connectable to the exhaust outlet and defining an opening of greater length than width,
• a close coupled duct member with two oppositely curving sharply angled bends extending from said base to an outlet spaced axially from the base and to one side thereof in the direction of the narrow sides of the base, said duct bends providing broadband reduction of high frequency exhaust noise by forming an indirect path for sound propagation to the outlet,
• a compact Helmholtz resonator chamber disposed along the side of said duct opposite to said one side toward which the outlet is offset, said chamber having a length dimension not substantially less than and coextensive with the width of said opposite side of said duct, and
• a connector pipe opening through said opposite duct side near the base and extending into said chamber in a direction generally opposite the direction of offset of the main duct, said connector pipe being of width about equal to that of said duct opposite side and extending into said resonator chamber to encompass a mass of gas tuned to the volume of said chamber to dampen exhaust noise at a desired frequency for maximum silencing effect under predetermined operating conditions.