Trionic. Trionic is an engine management system developed by Saab Automobile. It consists of an engine control unit (ECU) that controls 3 engine aspects: 
 Ignition timing
 Fuel injection
 Acts as a boost controller.
The numerical prefix 'tri-' yes (Tri being three) in Trionic. 'Ion' comes from the fact that it uses ion current, measured by the spark plugs between combustion events which acts as a sensor for knock, misfire and synchronization detection. The ion current stream which was developed within the ion sensing system due to combustion can be deduced by monitoring the secondary current of the ignition coil. Using the value and wave shape of the current, after the actual spark event, the quality of the actual combustion process is determined, thus allowing the engine control unit to optimize the timing of the spark for the best engine performance while keeping emissions low on a much wider range of rpms.

Since Trionic 7, the throttle and thereby the air charge has also been electronically controlled, but the name "Trionic" was not changed accordingly as it was determined that the name had value.

History 
The SAAB Trionic engine management system was developed for the 9000 and 'New Generation' 900 turbocharged engines. The engine management system was first utilized on the Saab B204 and B234 "H" engines to monitor and control the fuel injection system and turbocharging pressure control.

The Trionic 5.2 and 5.5 systems utilized the manifold absolute pressure (MAP) sensor and the intake air charge temperature sensor to calculate the fuel injection curves, while the Trionic 7 and 8 systems are mass air flow type. Both systems have substantial differences that prevent utilization of components between the two. Generally speaking, engine tuners prefer the easier to work with Trionic 5 systems over the Trionic 7 and 8 which are more restrictive in what can be manipulated within the software.

The intellectual rights to the Trionic 5 and 7 systems were sold in 2009 to BAIC, along with the Saab H Engine that it was designed for, as part of Saab's restructuring and transfer of ownership of General Motors to Spyker.

Models and ECU information

Trionic systems are shortened to indicate their version; for e.g. T5, T7, T8, etc. The engines with T5 had red direct ignition modules which differentiated them visually from the T7 models which had a black ignition module. The ignition module on both T5 and T7 are an integral ignition coil and electronics that plug directly onto the spark plugs without the use of spark plug wires that were typically used in most engines at the time.

SAAB Models Utilizing Trionic Engine Management System:
2nd Generation 900 ("NG900") 1994-1998  T5
9000 1994-1998  T5
1st Generation 9-3 1998-2000  T5 (Except Viggen, which is T7)
1st Generation 9-3 2000 to 2002  T7
1st Generation 9-5 1998-2010 4Cyl  T7
2nd Generation 9-3 2003 to 2011 4cyl  T8

Glossary
Sources include: Engine management system SAAB Trionic T5.5
 APC, Automatic Performance Control
 CDM, Combustion Detection Module 
 ECU, Engine control unit
 EGT, Exhaust gas temperature
 ETC, Electronic throttle control
 MAP, Manifold Absolute Pressure
 MIU, Main Instrument Unit
 ORVR, On board Refueling Vapor Recovery system
 PWM, Pulse-width modulation
 SID, Saab Information Display
 TCS, Traction control system
 TPS, Throttle position sensor
 TWICE, Theft Warning Integrated Central Electronics
 VSS, Vehicle Speed Sensor
 WOT, Wide Open Throttle

References

External links 
 , formerly a Community dedicated to giving Trionic power to the people! This site is no longer online. Founded by Andrew J. Weaver and Steven A. Hayes and supported by the global SAAB community. 
 trionictuning.com, community-driven exploration and development of new Trionic features, supported by the global SAAB community.

Engine control systems