Operation Manual

195Car care
Saab Trionic engine management
system
The Saab Trionic engine management
system is a unique Saab development that
combines sequential multiport fuel injection,
electronic distributorless ignition and turbo-
charger boost pressure control into one sys-
tem.
The Trionic engine control module (ECM)
monitors many different engine parameters
such as:
• Intake manifold pressure.
• Intake air temperature.
• Crankshaft position.
• Engine coolant temperature.
• Throttle position.
• The oxygen content of the exhaust gases.
The ECM receives information regarding
engine knocking from a sophisticated feed-
back function in the ignition discharge unit.
By processing all of this information, the Tri-
onic system can control fuel injector open-
ing duration, ignition timing and turbo-
charger boost pressure to provide excellent
engine performance while maintaining low
emissions and fuel consumption.
ORVR (Onboard Refueling Vapor
Recovery)
All hydrocarbons formed when refueling will
be recovered by the car and not released
into the atmosphere. The hydrocarbons are
absorbed in an evaporative emission canis-
ter. When the engine is subsequently
started, the evaporative emission canister is
gradually purged as air is sucked into it
through a shut-off valve. The hydrocar-
bon/air mixture passes through the evap
canister purge valve and into the engine
where it is burned. "Refueling", see page
157.
NOTE
The Trionic engine management system
continuously monitors the operation of
these systems and has on-board diag-
nostic capabilities (OBD II). If the CHECK
ENGINE light in the main instrument illu-
minates, the Trionic ECM has detected a
problem. The car will continue to operate,
but performance may be diminished. You
should have your car checked by a Saab
dealer as soon as possible.