TURBOCHARGERS & SUPERCHARGERS

CHAPTER 7

FORCED INDUCTION

• 4 WAYS TO INCREASE COMPRESSION– SUPERCHARGING– TURBOCHARGING– CHEMICAL– ENGINE

MODIFICATION

TURBOCHARGERS

• COMPRESSES AIR GOING INTO COMBUSTION CHAMBER

• DEPENDS ON RAPID EXPANSION OF EXHAUST GASES LEAVING COMBUSTION CHAMBER

• TURBO LAG IS A CHARACTERISTIC

TURBOCHARGER PARTS

• TURBINE• SHAFT• COMPRESSOR• WASTEGATE• ACTUATOR• CENTER HOUSING

– CONTAINS COOLING SECTION

222C

VANE WHEELS

TURN AT 100,000 RPM

TURBO CYCLE

• EXHAUST GAS FORCES TURBINE TO ROTATE• COMPRESSOR FORCES (PACKS) CREATING A

DENSE AIR-FUEL MIXTURE• CREATES A POSITVE PRESSURE (BOOST)

223C

BOOST PRESSURE CONTROL

• WASTEGATE DIAPHRAGM

• CONTROLS BOOST PRESSURE

• MECHANICAL OR ELECTRONICALLY CONTROLS WASTEGATE OPERATION

224C

TURBOCHARGER COOLING

• EXHAUST FLOW PAST TURBINE WHEEL CAUSES HIGH TEMPS

• WATER COOLING• OIL COOLING• OIL SEALS • MUST LET TURBO

COOL DOWN ON SHUTOFF

HEAVY DUTY APPLICATION

• SAME PRINCIPLE AS SMALLER ONES

• BOOST PRESSURE SLIGHTLY HIGHER

• COOLING A LOT MORE IMPORTANT

• DIESEL TRUCK, LOCOMOTIVE, HEAVY EQUIPMENT

POWER OUTPUT COMPARISON

ROTARY RACING ENGINE

MAINTENANCE / PROBLEMS

• LACK OF OIL• DIRTY OIL• MECHANICAL DAMAGE OF VANE

WHEELS• WASTEGATE CONTROL PROBLEMS• OIL CAKING

DIAGNOSIS

• OIL LEAKS, HOSES, LINKAGES• BLUE SMOKE• EXCESSIVE NOISE• EXHAUST LEAKS• TEST BOOST PRESSURE• TURBO R & R REQUIRES PRE-

LUBING

PAGE 302 LAB

SUPERCHARGERSSUPERCHARGERS

SUPERCHARGER OPERATION

• BELT OR GEAR DRIVEN• ROTORS ACT LIKE A PUMP AND

COMPRESS AIR (PAGE 310 LAB)• SUPERCHARGER SPEED IS LIMITED BY

ENGINE SPEED -TURNS A LOT SLOWER• SOMETIMES USED WITH INTERCOOLER

TO COOL AIR• BYPASS BUTTERFLY VALVE 230 LAB

BLOWN ENGINE

• MORE RELIABLE THAN A TURBO

• MUST RECEIVE PROPER LUBRICATION

• IMPROVED THROTTLE RESPONSE OVER A TURBO