In spark-ignition internal combustion engines, knocking occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but when one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front. The fuel–air charge is meant to be ignited by the spark plug only, and at a precise point in the piston's stroke. Knock occurs when the peak of the combustion process no longer occurs at the optimum moment for the four-stroke cycle. The shock wave creates the characteristic metallic "pinging" sound, and cylinder pressure increases dramatically. Effects of engine knocking range from inconsequential to completely destructive.
Engine tuning is the adjustment or modification of the internal combustion engine or Engine Control Unit (ECU) to yield optimal performance and increase the engine's power output, economy, or durability. These goals may be mutually exclusive; an engine may be de-tuned with respect to output power in exchange for better economy or longer engine life due to lessened stress on engine components.
Ignition systems are used by heat engines to initiate combustion by igniting the fuel-air mixture. In a spark ignition versions of the internal combustion engine, the ignition system creates a spark to ignite the fuel-air mixture just before each combustion stroke. Gas turbine engines and rocket engines normally use an ignition system only during start-up.
The GM Ecotec engine, also known by its codename L850, is a family of all-aluminium inline-four engines, displacing between 1.4 and 2.5 litres. Confusingly, the Ecotec name was also applied to both the Buick V6 Engine when used in Holden Vehicles, as well as the final DOHC derivatives of the previous GM Family II engine; the architecture was substantially re-engineered for this new Ecotec application produced since 2000. This engine family replaced the GM Family II engine, the GM 122 engine, the Saab H engine, and the Quad 4 engine. It is manufactured in multiple locations, to include Spring Hill Manufacturing, in Spring Hill, Tennessee, with engine blocks and cylinder heads cast at Saginaw Metal Casting Operations in Saginaw, Michigan.
General Motors' Opel subsidiary in Europe designed a compact V6 engine with an unusual 54° vee angle. It was an iron block/aluminum head DOHC design with four valves per cylinder. All 54° engines were assembled at Ellesmere Port in England.
The Trionic 8 is an advanced engine management system in the Trionic series, created by Saab Automobile. It is used in both Saab 9-3 and Opel Vectra vehicles, and is available with 150, 175 and 210 horsepower (160 kW) engines. It will also be used for a flexifuel version starting production spring 2007. Saab Trionic T8 has been developed by Saab and is a very advanced engine management system. The Engine Control Module (ECM) is used principally to regulated the air mass, fuel and ignition timing.
Lean-burn refers to the burning of fuel with an excess of air in an internal combustion engine. In lean-burn engines the air–fuel ratio may be as lean as 65:1. The air / fuel ratio needed to stoichiometrically combust gasoline, by contrast, is 14.64:1. The excess of air in a lean-burn engine emits far less hydrocarbons. High air–fuel ratios can also be used to reduce losses caused by other engine power management systems such as throttling losses.
The manifold absolute pressure sensor is one of the sensors used in an internal combustion engine's electronic control system.
The anti-lag system (ALS) is a method of reducing turbo lag or effective compression used on turbocharged engines to minimize turbo lag on racing or performance cars. It works by delaying the ignition timing and adding extra fuel to balance an inherent loss in combustion efficiency with increased pressure at the charging side of the turbo. This is achieved as an excess amount of fuel/air mixture escapes through the exhaust valves and combusts in the hot exhaust manifold spooling the turbocharger creating higher usable pressure.
Chip tuning is changing or modifying an erasable programmable read only memory chip in an automobile's or other vehicles electronic control unit to achieve superior performance, whether it be more power, cleaner emissions, or better fuel efficiency. Engine manufacturers generally use a conservative electronic control unit map to allow for individual engine variations, as well as infrequent servicing and poor-quality fuel. Vehicles with a remapped electronic control unit may be more sensitive to fuel quality and service schedules.
An engine control unit (ECU), also called an engine control module (ECM), is a device which controls multiple systems of an internal combustion engine in a single unit. Systems commonly controlled by an ECU include the fuel injection and ignition systems.
Motronic is the trade name given to a range of digital engine control units developed by Robert Bosch GmbH which combined control of fuel injection and ignition in a single unit. By controlling both major systems in a single unit, many aspects of the engine's characteristics can be improved.
In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke.
Digifant is an Engine Management System operated by an Engine Control Unit that actuates outputs, such as fuel injection and ignition systems, using information derived from sensor inputs, such as engine speed, exhaust oxygen and intake air flow. Digifant was designed by Volkswagen Group, in cooperation with Robert Bosch GmbH.
Saab Direct Ignition is a capacitor discharge ignition developed by Saab Automobile, then known as Saab-Scania, and Mecel AB during the 1980s.
Trionic T5.5 is an engine management system in the Saab Trionic range. It controls ignition, fuel injection and turbo boost pressure. The system was introduced in the 1993 Saab 9000 2.3 Turbo with B234L and B234R engine.
The Trionic T5.2, an advanced engine management system in the Trionic series, was introduced in Saab 9000 year 1993 and was discontinued the same year. This engine management system was used on the "long block" engines. It was superseded by the Trionic T5.5 engine management system.
The Modular Engine Management System, or MEMS, is an electronic control system used on engines in passenger cars built by Rover Group in the 1990s. As its name implies, it was adaptable for a variety of engine management demands, including electronically controlled carburetion as well as single- and multi-point fuel injection. The abbreviations "SPi" and "MPi" refer to the single-point and multi-point injection configurations, respectively.
