Aneroid boost head compensator control (AFC or Air Fuel Control)
The picture is from the Bosch VE manual, I believe there is a link to it on this site somewhere.
The boost compensator ensures the amount of injection fuel is in proportion to the air within the engine cylinder for combustion of the fuel and is then increased with the hp of the engine. When the engine is running, pressurized air from the turbo passes through the connecting tube from the engine air manifold to the boost compensator chamber (AFC pump top). Inside the chamber is a diaphragm which is connected to a pushrod (eccentric cone also known as "fuel pin") which is in turn coupled to the pin. Movement of the diaphragm is opposed by a spring, for any movement at the pin the air pressure on the the diaphragm must be higher than spring tension. When the engine RPM and load increase and air pressures in the connecting tube become high enough to overcome the tension of the spring, the diaphragm and pushrod are pushed down. The tapered "eccentric cone or fuel pin" causes the compensator pin to move in as the taper lowers and narrows, forcing the fuel control rack toward an increased fuel position. The boost compenstor reacts to the engine inlet air pressure regardless of the governor. When turbo boost reaches maximum the quantity of fuel injected will be equal to the stroke of the aneroid boost compensator pin, in additon to the normal full load injection amount that is determined by the governor full load stop bolt.
Fuel Pins with a more aggressive taper can be bought ($125 and up) or as many people have done, they can be ground DIY style, if you ruin one or want to grind one yourself they are approx. $100 new from an authorized Bosch shop. Search any of the popular diesel forums for additional Info. I would recommend checking the FAQ sections or Tech sections for additional info on the Bosch VE Fuel Injection Pump
The picture is from the Bosch VE manual, I believe there is a link to it on this site somewhere.
The boost compensator ensures the amount of injection fuel is in proportion to the air within the engine cylinder for combustion of the fuel and is then increased with the hp of the engine. When the engine is running, pressurized air from the turbo passes through the connecting tube from the engine air manifold to the boost compensator chamber (AFC pump top). Inside the chamber is a diaphragm which is connected to a pushrod (eccentric cone also known as "fuel pin") which is in turn coupled to the pin. Movement of the diaphragm is opposed by a spring, for any movement at the pin the air pressure on the the diaphragm must be higher than spring tension. When the engine RPM and load increase and air pressures in the connecting tube become high enough to overcome the tension of the spring, the diaphragm and pushrod are pushed down. The tapered "eccentric cone or fuel pin" causes the compensator pin to move in as the taper lowers and narrows, forcing the fuel control rack toward an increased fuel position. The boost compenstor reacts to the engine inlet air pressure regardless of the governor. When turbo boost reaches maximum the quantity of fuel injected will be equal to the stroke of the aneroid boost compensator pin, in additon to the normal full load injection amount that is determined by the governor full load stop bolt.
Fuel Pins with a more aggressive taper can be bought ($125 and up) or as many people have done, they can be ground DIY style, if you ruin one or want to grind one yourself they are approx. $100 new from an authorized Bosch shop. Search any of the popular diesel forums for additional Info. I would recommend checking the FAQ sections or Tech sections for additional info on the Bosch VE Fuel Injection Pump