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

SUPERCHARGERS

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