Filter
Top Products
1994 Volvo 850
exhaust emissions.
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 provide optimum conditions
for combustion and efficient reduction of the three major pollutants (hydrocarbons, carbon monoxide
and oxides of nitrogen (NOx) by a three-way catalytic converter.
Secondary Air Injection (certain models)
This system adds air to the hot exhaust gases as they are expelled from the engine. This causes a
secondary combustion of residual hydrocarbons and carbon monoxide, resulting in lower emissions
levels in the exhaust gases.
A-roll over valve, B-vacuum valve, C-inlet manifold, D-charcoal canister, E-fuel tank
Evaporative control system
The car is equipped with a gas evaporative control system, which prevents gasoline fumes from being
released into the atmosphere. The system is comprised of an expansion chamber in the fuel tank, a roll-
over valve on the cross member in front of the fuel tank and a charcoal canister with a built-in vacuum
valve under the left-front wheel housing. The components are interconnected by hoses which channel
fuel vapor from the gas tank to the charcoal filter, where it is stored until the engine is started and then
drawn into the engine's air intake system.
file:///K|/ownersdocs/1994/1994_850/94850_8_6.html (4 of 9)12/30/2006 9:48:51 AM