Automobile

1. AIR INDUCTION AND EXHAUST SYSTTEM
AIR SYSTEM FLOW
Air cleaner
Turbo charger
(compressor side)
After cooler/Intake manifold
Intake ports/valves
Combustion chamber
Exhaust piping
silencer
Turbo charger
(turbine wheel
Exhaust manifold
Exhaust valves/ports

2. Air system
• Function
• To supply air for complete combustion of fuel
• To take exhaust gases out of engine, hence divided into
two parts as
• Air intake system and Exhaust system
• Air intake system requirements
• Air supplied to the engine must be
• Sufficient- 1 ltr of fuel needs 12,500 ltrs of air for
complete burning. Oxygen in air is essential for burning
• Clean air- dust in air is harmful for engine-free of dust
particles
• Cool air- air at high temp will ignite fuel early, air at
high temp is thin and has less oxygen
• Dry air- air with moisture will have less oxygen,
moisture in combustion chamber is harmful to engine

3. Components in air intake system
• Air cleaner- element/housing
• Hump hose
• Suction pipe and vacuum indicator
• Turbocharger
• Air crossover connection
• Clamps
• After cooler/inter cooler
• Intake manifold
• Intake valves
• Combustion chamber

4. Air intake system
• Hump hose- leads the air from cleaner to turbo or
intake manifold-connects housing & suction pipe-
perfect sealing with the help of clamps-strong
enough to withstand vacuum
• Suction pipe- always under suction, transfers clean
air to turbocharger or intake manifold, vacuum
indicator mounted on it, even a hose can be
connected for remote vacuum indicator.
• Vacuum indicator- an easy way to know the
condition of air cleaner, red band is shown when
restriction beyond a limit, can be seen from a
distance.

5. Turbocharger
• Turbine casing and turbine wheel
• Impeller & casing
• Bearing housing
• Water cooled bearing housing also provided
• Rotates on the waste energy of exhaust gases
• Exhaust gases are directed on turbine wheel
• Clean air from air cleaner is pressurized by impeller wheel
• Advantages of a turbocharger
• More air-more fuel can be burnt-more power
• Better air/fuel ratio at all speeds-less pollution
• More air at lower speeds- better fuel combustion
• Self compensating at high altitudes
• Pressurized air manifolds – reduce combustion noise
• Utilizes energy from exhaust gases-more efficient
• Noise reduction- less noise

6. Crossover connection
• Leads the pressurized air from turbo to intake manifold,
always pressurized, sealed with clamps & gaskets
After cooler
• cool air means-more oxygen-more fuel- more power
• Fitted in housing or intake manifold
• A bundle of tubes to circulate engine coolant
• Pressurized hot air passes over this element
• Heat from air absorbed by coolant
• Drops the temp of air from 300* to 218* F
• Coolant flows inside the tubes
• Air flows through the fins
• Heat flow is from hotter fluid to colder fluid
• Chocking of tubes from inside or the fins from outside
will result in high intake air temperature

7. Intake manifold
• Leading air to the intake ports of cylinder heads
• Under suction in naturally aspirated engines
• Pressurized in turbocharged engines
• Sealing with gaskets
• Single or multiple configuration
• Distributes air evenly to all intake ports
Exhaust system
• Components in exhaust system
• Exhaust valves
• Exhaust manifold
• Exhaust piping
• Exhaust system supports
• Silencers/mufflers
• Rain caps

8. • Requirements of exhaust system operation
• Exhaust back pressure within the limits
• Noise reduction
• Prevent rain water entry into cylinder
• Exhaust piping support
• Lagging
Problems in air system and their causes/trouble shooting
• Trouble shooting tips
• An organized study of the problem
• For investigation & correction of difficulty
• Think before acting-study problem thoroughly
• Ask for any warnings, previous repairs, any similar trouble
before, is it safe to continue running engine
• Do easiest and obvious things first
• Double check before beginning disassembly
• Find and correct basic cause of trouble

9. • Blow – by means
• Combustion gases leak into crankcase due to wear of piston
rings/liners
• Blow-by results into –high crank case pressure
• Oil seal leakages
• Sludge formation in oil
• Improper lubrication of parts
• Reduced engine life
• Early engine overhaul
• High cost of overhaul
• Reasons for dust entry in combustion chamber
• Improper sealing of air cleaner element
• Porous/poor quality of paper element
• Torn air cleaner element
• Split tubing/piping
• Loose clamps
• Cracked hump hoses

10. • Use of broken gaskets
• Loose/cracked air intake manifolds
• Missing washers/wing nuts in air cleaners
Effects of dirt/dust entry in to engine
• Dirt forms abrasive paste oil
• Wear of piston rings/liners/valves/guides
• High lub oil consumption
• Excessive blow-by
Loss of power or engine not taking load
• Restricted air flow
• Incomplete combustion of fuel
• Engine not developing full H.P

11. Reasons for restriction to air flow
• Inlet cap/path obstruction
• Less diameter of air intake piping
• Excessive/sharp bends in intake systems
• Faulty location of air cleaner
• Poor quality of air filter/paper
• Chocked air cleaner element
Restrictions to air flow – tips
• Water manometer to measure restriction
• New element -8 to 15 inches of water
• Dirty element -25 inches of water
• Vacuum indicator showing red flag
• Avoid suction of leaking exhaust gases
• Never use torn element

12. Effects of restricted/less air to engine
• Incomplete combustion of fuel
• Heavy black smoke
• Low power/loss of power
• Hard starting/failure to start
• Reduced fuel economy
• Excessive lube oil consumption
• Carbon deposition in combustion chamber
Reasons for high back pressure
• Longer exhaust pipe lines
• Less pipe diameter
• Too many bends in the system
• Sharp bends
• Wrong location of silencer

13. Effects of excessive back pressure
• High combustion temperature causing early burning of
fuel…. Detonation… resulting in
• Piston crown burning
• Liner wall scuffing
• Piston rings scuffing
• Connecting rod bearing wear
Excessive back pressure results in
• Low power overheating(high coolant temperature)
• Poor fuel economy
• High engine wear rate
• Early bearing failure
• Carbon deposition on valves and pistons

14. Water entry or accumulation results in
• Hydraulic lock
• Early cylinder failure
• Rusted out pipe and fittings
• High noise level due to damages