NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 EQUIPMENT DESCRIPTION AND DATA—Continued 0002 00 LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - CONTINUED j. Manifold Air Induction and Heater System. The manifold air induction and heater system is represented in flow diagram form in Figure 5. (1) Turbosupercharger Assemblies. Exhaust gas driven turgosupercharger assemblies, one for each bank of cylinders, are mounted on each side of the engine, at the rear. The turbosuperchargers increase the pressure of the intake air thereby delivering a higher density air to the cylinders as compared with a nonsupercharged engine. The higher density air, with a proper fuel flow, increases engine power. (2) Intake Manifold Heater. The intake manifold, which distributes induction air to each bank of cylinders, is equipped with an electrically operated flame type intake manifold heater. The heater is provided as an aid for cold weather starting and cold weather operations. Operation of the heater switch (in the vehicle operator’s compartment) energizes the manifold heater fuel solenoid valve, the heater ignition unit, and spark plug for each heater simultaneously. Fuel is hand pumped through the manifold heater fuel filter and fuel solenoid valve and sprayed into the intake manifold. The fuel is ignited by the spark plug and burns in the intake manifold as the engine is cranking, and the flame heats the incoming air. This flame-heated air and the products of combustion are fed directly into the cylinders with little heat loss. This results in an immediate engine response and assures complete combustion at low engine rpm and at no-load operating conditions with low ambient temperature. (3) Solenoid Valve. The manifold heater fuel inlet solenoid valve prevents fuel pumped by the fuel pump assembly from entering the air intake manifold heater unless the heater system is energized. A manifold heater fuel return check valve and solenoid valve are located at the rear of the engine. The solenoid valve is also energized (opened) when the ignition unit and heater spark plugs are energized to permit excess fuel to be returned to the fuel tanks. The main fuel backflow valve prevents back flow of the fuel when the purge pump in the driver’s compartment is actuated. NOTE Smoke generating system will not produce smoke if the vehicle fuel is JP-8. k. Smoke Generating System. The smoke generating system, Figure 6 uses the engine fuel pump to supply diesel fuel, from the vehicle fuel tanks, to two solenoid valves mounted at the rear of the engine. When the solenoid valves are energized (opened) they allow diesel fuel to be sprayed into the engine exhaust system. The fuel vaporizes and exits together with the engine exhaust gases. The fuel vapor cools on contact with the ambient air and condenses to form a dense homogeneous smoke screen. The electrical power to energize the solenoid valves is supplied by the air cleaner blower motor circuit. This prevents accidental activation of the smoke generating system when the engine is not running. l. Exhaust System and Turbosupercharger. The exhaust system consists of four manifolds, one for each group of three adjacent cylinders. The two exhaust manifolds on each cylinder bank are connected to the turbosupercharger on their respective side of the engine. Exhaust gases from each side of the engine enter a turbosupercharger and are forced around a turbine housing, radially inward, and through a nozzle ring toward the turbine wheel. The exhaust gases drive the turbine wheel, which in turn drives the compressor wheel since both wheels are on a common shaft. Intake manifold air enters at the center of the compressor wheel and flows radially outward through a diffuser section into the compressor housing. The air at increased velocity then leaves through a tangential outlet on the outside of the compressor housing and enters the intake manifold. The exhaust gases are expelled from the turbosuperchargers into the vehicle exhaust system. 0002 00-11 Change 1