AIR INTAKE SYSTEM
Supercharging – The process of increase air pressure more than atmospheric pressure and deliver in cylinder for fuel combustion is called supercharging.
It increases efficiency of the engine up to 50 % in this type of engine fuel burn with atmospheric air having pressure. In diesel loco Turbo Super Charger is provided for supercharging. Turbo Super Charger – TSC is provided at free end, above after cooler. It works with the help of exhaust gasses. TSC having four casing
1. Gas inlet casing
2. Turbine casing
3. Intermediate casing
4. Blower casing
Gas inlet casing is connected with exhaust manifold. 14 exhaust elbows connected in exhaust manifold. R1 & L1 exhaust elbow are connected directly to gas inlet casing. One dome is provided in this casing. Rotor shaft is fitted in intermediate casing; turbine and blower are fitted on this shaft. Turbine is fitted in turbine casing and blower in blower casing. Gas inlet casing is connected to turbine casing through nozzle ring. One side of blower casing connected with cyclonic filter and other with expansion joint to after cooler. TSC cooled by engine coolant. Rotor shaft bearing is lubricated by engine lube oil system.
Working - Exhaust gases discharged by engine goes to gas inlet casing of TSC through exhaust manifold. In this casing gasses gets the direction with the help of dome and nozzle ring and hit the turbine blades and goes off to atmosphere through chimney. When turbine starts rotating same time blower also starts rotating since fitted on the common shaft. Partial vacuum is creating in blower casing hence atmospheric air flow from cyclonic filter.
Blower compress the air into after cooler, where it cools with water hence its density is increased. The other end of after cooler is connected to ‘V’ gallery where the pressurized air is collected and collected air pressure is called Booster Air Pressure. Booster Air Pressure gauge is provided in Loco Pilot cab. Maximum BAP is 1.97 kg/cm2 . At the time of suction stroke each cylinder is charged with super charged air through inlet elbow.
After cooler - To increase the density and reduces the temperature of air, this is provided below TSC on engine free end. It has U shaped pipes, through which water passes from inlet to outlet. The air is cooled around the U shaped pipes through radiation process. The cooled and dense air is stored in ‘V’ gallery. Tale - tell pipe provided in bottom of after cooler, if water leakage through it, fail the loco and inform the PCOR.
