Volvo V70 Automobile User Manual


 
2006 VOLVO V70
pg. 153 Fuel/emissions systems
Fuel system
The fuel system continually compensates for variation in engine load, speed and temperature. A mass air
flow sensor continuously measures the inducted air and makes rapid adjustments for changes in air
temperature and density, to balance fuel economy, emissions, and engine power requirements.
Heated oxygen sensor
This is an emission control system designed to reduce emissions and improve fuel economy. The heated
oxygen sensor monitors the composition of the exhaust gases leaving the engine. The exhaust gas
analysis is fed into an electronic module. This adjusts the air/fuel ratio to improve combustion and
reduce the three major pollutants (hydrocarbons, carbon monoxide, and oxides of nitrogen (NOx)) via a
three-way catalytic converter.
Crankcase ventilation
The engine is provided with positive crankcase ventilation which prevents crankcase gases from being
released into the atmosphere. Instead, the crankcase gases are routed to the intake manifold and
cylinders.
PremAir®
On the surface of the radiator in the engine compartment, there is a special coating called PremAir®.
PremAir® works as a catalytic converter, converting most of the ozone passing through the radiator into
oxygen, thereby reducing harmful ground-level ozone.
Evaporative control system
The car is equipped with an evaporative control system, which prevents gasoline vapor from being
released into the atmosphere.
The system consists of a fuel tank with filler pipe and cap, two rollover valves, a Fill Limit Vent Valve
(FLVV), vapor vent lines, a charcoal canister, a purge line, and a purge control valve and engine
connections. In addition, there is a pressure sensor connected to the fuel tank and a filter-protected
Canister Close Valve (CCV) on the atmospheric side of the canister, for system diagnosis.
The gasoline vapor is channeled through the rollover valves and the FLVV via the vapor vent lines into
the charcoal canister, where it is stored. When the engine is started, the gasoline vapor is drawn from the
charcoal canister to the engine's air intake system and into the combustion process.
NOTE:
Overfilling the fuel tank can cause damage to the evaporative control system.
If the fuel filler cap is not closed tightly or if the engine is running when the car is refueled, the
Malfunction Indicator Lamp may indicate a fault.
During a transitional period, a small number of service stations may still have fuel nozzles that are not
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