SERVICE MANUALOn a turbocharged diesel engine (Fig. 3), theturbocharger supplies air under pressure to the intakemanifold which provides a greater amount of air to thecombustion chamber. The fuel injection system iscalibrated to inject the correct amount of fuel for theincreased volume of air.Fig. 31. Turbocharger2. Fuel InjectorThe turbocharger, in addition to exhaust volumeand velocity, depends upon exhaust heat. Under loadedconditions at maximum fuel delivery, the turbochargerbecomes very efficient and supplies the increased airvolume needed to support proper combustion (Fig. 4).Since the turbine speed is governed by theexhaust energy of the engine at any speed, theturbocharger delivers the correct volume of air at anythrottle position. Also, less air resistance at higherelevations allows the turbocharger to spin faster andmaintain correct air delivery, thereby avoiding the powerloss and excessive smoking that occurs on naturallyaspirated and supercharged engines at high altitude.Fig. 4. Turbocharger CycleA.Compressor Wheel Speed Increases asExhaust Expansion Increases.B.Increased Fuel Consumption RequiresGreater Air Intake.C.Exhaust Temperature Increased withGreater Fuel Consumption.D.Increased Exhaust Temperature Results inGreater Expansion within Turbine Housing.The basic operating principles of theturbocharger are as follows:The engine exhaust is directed into the turbine housing(Fig. 5). As the exhaust passes through the nozzle ringvanes, it gains velocity and strikes the turbine wheelvanes. This action spins the turbine wheel shaft to whichthe compressor wheel is attached.As the compressor wheel turns, it draws air from the aircleaner into the compressor housing, compresses it andforces it into the intake manifold. This provides a greatervolume of air in the combustion chamber. Because agreater volume of airCTS-4104PRINTED IN UNITED STATES OF AMERICAPage 4
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
