PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IC-G-D-40-002e B
October 2010
EXHAUST SYSTEM AND VENTILATION OF THE OIL SUMP
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5. EXHAUST GASES OUTLET LINE
The exhaust gases produced by combustion leave the cylinders through the exhaust valves in the cylinder heads.
They are expelled to the exhaust manifold during the up stroke of the pistons.
In naturally aspirated engines, the exhaust gases go out of the engine through the exhaust directly. Customer has
to fit the gas outlet line to this exhaust.
In supercharged engines, the exhaust gases flow from the exhaust manifold into the turbocompressor(s) that
make(s) use of the energy of the exhaust gases to compress the intake air.
Finally, the gases go out into the atmosphere through the gas outlet line provided with flexible joints that absorb
expansion caused by the high temperatures involved.
The exhaust pipe will also be fitted with an exhaust gas silencer to reduce the noise produced in all internal
combustion engines and, where appropriate, with a catalytic converter to reduce polluting emissions.
6. CRANKCASE GAS BREATHER
Crankcase ventilation aims to eliminate the combustion gases that enter the crankcase through the clearance
between piston rings and piston liners. Those gases sweep oil along, which must be separated.
Ventilation takes place through a tap in the front or rear cover of the engine block. There, an elbow directs the
gases to a gridiron separator.
A. Open System
In an open crankcase ventilation system, gas-borne oil is separated in a separator (and drawn off oil returns to
the oil sump), while clean gases are expelled to the outside through a duct or pipeline. Refer to Product
Information Sheets IC-C-D-25-007e and IT-C-A-25-016e.
B. Closed System or Gas Recirculation System
In a closed system, the blow-by gases flow first through a separator and then through a specific filter that also
directs drawn off oil to the oil sump. Clean gases are fed back into the intake system, at a point located between
the intake filter and the carburettor. See specific Product Information Sheet IC-C-D-25-006e.
2.7.9
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