Fuel Delivery and Air Induction: Description and Operation

The V8-379 (6.2L) diesel engine is similar in many ways to gasoline engines, however, in the diesel engine air alone is compressed in cylinder; then after the air has been compressed, a charge of fuel is sprayed into the cylinder and ignition occurs due to the heat of compression. Due to the increased compression and resultant increase in combustion temperatures, major differences are evident in the cylinder heads, combustion chambers, fuel distribution system, intake manifold and engine mechanical components.
The cylinder block, crankshaft, main bearings, connecting rods, pistons and wrist pins are all heavy duty designs, due to the higher compression ratios, and the main bearing caps are 4 bolt design to provide rigid crankshaft support, while minimizing stress. Roller hydraulic lifters are used to minimize wear on the forged steel camshaft, and intake and exhaust valves are of special alloy material to combat the higher internal operating temperatures. Steel alloy prechamber inserts are installed in the combustion chambers and are serviced separately from the cylinder head. Injector nozzles and glow plugs are threaded into the cylinder head to allow direct fuel delivery and to provide chamber pre-heating.
The injector nozzles are spring loaded and designed to open and deliver fuel at specifically calibrated fuel pressures. Fuel is delivered into the high swirl pre-combustion chambers which mix fuel and air to provide an efficient fuel burn and low emissions. The glow plugs are used to heat the pre-chambers, and assist starting. In addition, a block heater is used to aid starting in cold climates. Because the intake manifold is always open to atmospheric pressures no engine vacuum supply is available, and a vacuum pump is installed to supply vacuum to components such as A/C and cruise control.