Alfa Romeo 166 Booklet page 131

WARNING
Due to the high temper-
ature reached while the
catalysts are working, it is advis-
able not to park the car over in-
flammable material (paper, fuel
oils, grass, dry leaves, etc.).
Lambda sensors
The lambda sensors detect the oxygen
content in the exhaust gas.
The signals transmitted by the Lambda
sensors are used by the electronic control
unit of the injection-ignition system to ad-
just the air-fuel mixture.
Anti-evaporation system
(only petrol versions)
As it is impossible, even when the en-
gine is switched off, to prevent the forma-
tion of fuel vapours, a system has been
devised which traps them in a special car-
bon container.
During operation of the engine these
vapours are withdrawn and sent to com-
bustion.
EMISSION REDUCING DEVICES
(diesel engines)
Oxidising catalytic converter
Converts the polluting substance in the
exhaust gases (carbon monoxide, un-
burnt hydrocarbons and particulate), thus
reducing the fumes and smell that are
typical of diesel engines.
The catalytic converter consists of a
stainless steel case that houses a ceramic
honeycomb coated with noble metal used
as a catalyst.
Exhaust gas recirculation system
(E.G.R.)
This system recycles, i.e. re-uses, a
varying percentage of the exhaust gases
depending on engine operating condi-
tions.
It is used, when necessary, to control ni-
tric oxides.
131