Saab Direct Ignition is a

capacitor discharge ignition Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. It w ...

developed by

Saab Automobile Saab Automobile AB () is a defunct automotive industry, car manufacturer that was founded in Sweden in 1945 when its parent company, Saab AB, began a project to design a small automobile. The first production model, the Saab 92, was launched in ...

, then known as Saab-Scania, and '' Mecel AB'' during the 1980s. It was first shown in 1985 and put into series production in the

Saab 9000 The Saab 9000 is an automobile produced by the Swedish company Saab from 1984 to 1998. Representing the company's foray into the executive car scene, it was developed as a result of the successes of the turbocharged 99 and 900 models. The 9000 re ...

in 1988. One of the first instances of using the system was for a

Formula Three Formula Three, also called Formula 3, abbreviated as F3, is a third-tier class of open-wheel formula racing. The various championships held in Europe, Australia, South America and Asia form an important step for many prospective Formula One driv ...

racing engine (on B202 basis) developed with the help of engine builder John Nicholson, first shown in the spring of 1985. The system has been revised several times over the years. The

ignition system An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc. The widest application for spark ig ...

together with the ignition coils form a single

transformer oil Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformers (wet transformers), some types of high-voltage capacitors, fluorescent lamp b ...

filled cassette (or two cassettes in the case of a V6 engine) which is placed directly on the

spark plug A spark plug (sometimes, in British English, a sparking plug, and, colloquially, a plug) is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air ...

s, without the need for a

distributor A distributor is an enclosed rotating switch used in spark-ignition internal combustion engines that have mechanically timed ignition. The distributor's main function is to route high voltage current from the ignition coil to the spark plugs ...

. It was later implemented with the Saab

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-' in Trion ...

Engine Management Systems as one of the first ion sensing ignition system on a production car. The system puts a low

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...

over the spark plugs when they are not fired to measure

ionization Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule i ...

in the cylinders. The ionic

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...

measurement is used to replace the ordinary knock

sensor A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...

and misfire measurement function.

Direct Ignition Cassette

The spark plugs are directly coupled to the "DIC" (or "IDM") which houses the ignition coils and electronics that measure cylinder ionization for use by the

engine management system.

References

{{reflist Ignition systems Engine technology Automotive technology tradenames Saab engines

Direct Ignition Cassette

See also

References