Negative rate shaping torque capsule

A governor for a compression ignition engine, the engine having a fuel system wherein individual fuel pumping elements, connected with injection nozzles, are actuated by cam followers engaging an engine driven cam shaft and the amount of fuel delivered by each pumping element is regulated by control sleeves operatively linked to a control rack, the governor is centrifugally actuated based upon the speed of an engine driven gear and controls the translation of the control rack and, in turn, the amount of fuel delivered by each pumping element, the governor comprising:

• a governor arm body having a central shaft bore, a pair of bearing arms and a main arm, the main arm having a mounting structure;
• a bearing member pivotally mounted between the bearing arms;
• a pivot arm having a first end and a second end, the first end being disposed in the mounting structure and pivotally journaled there, a portion of the mounting structure serving as a physical stop for the pivot arm;
• a tension arm roller mounted to the pivot arm;
• a rack roller mounted to the second end of the pivot arm;
• a tension arm attached to the main arm adjacent to the tension arm roller;
• and,
• a torque capsule (TC) spring interposed between the tension arm and the
• main arm so that the pivot arm can pivot relative to the main arm, but its motion is limited in a first direction by the physical stop, and in a second direction by the TC spring;
• wherein the TC spring holds the tension arm roller against the tension arm and in a static condition holds the pivot arm against the physical stop, as engine speed increases increased flyweight force causes an increase in the force of the tension arm roller against the tension arm, as speed increases further the flyweight force overcomes a preload of the TC spring causing the pivot arm to lift off its physical stop, in turn causing the governor arm assembly to bend at a joint where the pivot arm is mounted to the main arm, in turn causing the rack roller end of the pivot arm to move in a direction of increasing rack travel and as engine speed continues to increase, the rack roller continues to increase rack travel until the flyweight force overcomes a main governor spring, so that rack position is allowed to increase with increased engine speed, and decrease with decreased engine speed, thereby reducing the amount of fuel backup and preventing excess torque rise and reducing smoke and exhaust emissions.