Regulator for IC engine exhaust brake systems - has engine speed dependent pneumatic switch to relieve exhaust pressure

摘要

The regulator influences the pull side in the main brake cylinder to avoid peak pressures and subsequent engine damage. The exhaust pipe (3) has a pivoted brake flap (4) whose spindle is mechanically connected to a brake cylinder piston rod (8). The brake flap is h eld in the open position by a coil spring (11) fitted inside the cylinder on the push side (9) of the piston. Air pressure (14) introduced by the foot brake valve ( 13) on the push side (9b) of the piston (10) overcomes spring pressure to close the brake flap. Breaking occurs because the engine is drawing in air and unable to expell it as in 625095. An air pressure sensor (57) is fitted between engine block and cooling fan (58) to actuate a servo piston (50a) when the engine revolution speed exceeds a threshold limit. The servo piston is displaced to close a pneumatic switch (54) which stops the brake cylinder vent pipe (51). This allows compressed air from an auxiliary supply (54) to flow into the brake cylinder (9) via a restrictor and a non return valve.