Exhaust silencer for an agricultural tractor

Exhaust silencer for an agricultural tractor having a diesel engine with a cylinder capacity between 2.5 and 4 liters and a power rating of about 50-75 HP, comprising:

• a hollow tubular body of elliptical cross-section;
• respective end-walls closing the opposite ends of said body;
• an induction pipe, a portion of which traverses one said end-wall, and
• an exhaust gas outlet pipe traversing the other said end-wall,
• wherein the improvements consists in said silencer body having internal dimensions of 195 millimeters along a larger axis, 90 millimeters along a smaller axis, a length of 702 millimeters and comprising:
• a first dished baffle-plate located 55 millimeters from said one end-wall;
• a first resonance chamber defined by said one end-wall and said first baffle-plate;
• a second dished baffle-plate located 87 millimeters from said first baffle-plate;
• a second resonance chamber defined by said first and second baffle-plates;
• a third dished baffle-plate located 320 millimeters from said other end-wall;
• a first gas expansion chamber defined by said second and third baffle-plates;
• a second gas expansion chamber defined by said third baffle-plate and said other end-wall;
• two tubular ducts supported by said third baffle plate and having respective internal diameters of 30 millimeters and respective centres lying on said larger axis at a distance of 45 millimeters on each side of said small axis, each said duct extending for a length of 62 millimeters into said first expansion chamber and for a length of 37 millimeters into said second expansion chamber,
• and wherein:
• said resonance and expansion chambers are arranged in series longitudinally of said body;
• said portion of said induction pipe has an internal diameter of 45 millimeters and extends through said resonance chambers to said first expansion chamber, projecting into the latter for a length of 75 millimeters;
• said portion of said induction pipe has respective aperture means communicating with the respective said resonance chambers, and
• said exhaust gas outlet pipe has a portion which extends into said second expansion chamber for a length of 31 millimeters, said outlet pipe extending beyond said other end wall for a length of 600 millimeters.