PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IC-C-D-25-006e B
January 2015
DESCRIPTION OF A CRANKCASE GAS
RECIRCULATION SYSTEM
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1. INTRODUCTION
The crankcase gas recirculation system of the engine, also called the active system, is intended to feed the flow
of engine blow-by gases back into the intake air current in a clean and efficient manner and so:
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to eliminate one source of emissions, by burning these gases inside the engine, and thus to get one single
exhaust in accordance with the prevailing legislation in different countries;
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to clean the blow-by gas flow so that it is harmless when reintroduced into the engine;
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to regulate the blow-by gas flow so as to set optimum working conditions, fulfilling both internal criteria of
optimum cleanness and engine operation requirements.
Blow-by gases refer to the portion of combustion gases which passes through the combustion chamber sealing
rings into the crankcase, generating a higher pressure than the atmospheric one, and which must be released to
the outside of the machine room in order to avoid:
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plugging of the inlet filters;
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explosion and fire hazards;
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a polluted atmosphere harmful to the machine operators.
2. CONFIGURATION
A crankcase gas recirculation system (CGR) comprises the following parts:
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A crankcase (1) which collects the gases that escape from the combustion chamber through the interstice
between the piston rings and the cylinder liner.
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The blow-by gas breather (2) with drain It is made of one or various wire-mesh separators which separate the
gas-borne thick liquid drops and feed them back to the crankcase by gravity.
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Piping between separators and recirculation filter (6).
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Blow-by gas separator filter (3). All the liberated configurations have only one filter, except for terrestrial diesel
V-engines with air filters which have two gas separator filters and the HGM420/560, with the HGM filters
having the greatest filtering efficiency.
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An oil return pipe from the recirculation filter (5).
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Crankcase pressure control valve (4).
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Blow-by gas feed pipe to air intake (between air filter and carburettor) (6).
It is mandatory to follow the installation and assembly instructions defined in product information documents
IT-C-A-25-024e and IM-C-C-25-002e in order to ensure correct operation of each component as specified or
otherwise to be able to take the necessary corrective steps.
2.3.19
O&M_2.002211.810_A_10_2016
