FADEC - Full Authority Digital Engine Control.

FADEC is the acronym for Full Authority Digital Engine Control. It is a system consisting of a digital computer (called EEC /Electronic Engine Control/ or ECU /Electronic Control Unit/) and its related accessories which control all aspects of aircraft engine performance. FADECs have been produced for both piston engines and jet engines, their primary difference due to the different ways of controlling the engines.

Electronics' superior accuracy led to early generation analogue electronic control first used in Concorde's Rolls-Royce Olympus 593 in the 1960s. Later in the 1970s NASA and Pratt and Whitney experimented with the first experimental FADEC, first flown on an F-111 fitted with a highly modified Pratt & Whitney TF-30 left engine. The experiments led to Pratt & Whitney F100 and Pratt & Whitney PW2000 being the first military and civil engines respectively fitted with FADEC and later the Pratt & Whitney PW4000 as the first commercial 'Dual FADEC' engine.

The aircraft's thrust lever sends electrical signals (pilot's command, may also be the autothrottle) to the FADEC. The FADEC digitally calculates and precisely controls the fuel flow rate to the engines giving precise thrust. In addition to the fuel metering function, the FADEC performs numerous other control and monitoring functions such as Variable Stator Vanes (VSV's) and Variable Bleed Valves (VBV's) control, cabin bleeds and power off-takes control, control of starting and re-starting, turbine blade and vane cooling and blade tip clearance control, thrust reversers control, engine health monitoring, oil debris monitoring and vibration monitoring. The inputs come from various aircraft and engine sensors. Apart from the key parameters that are monitored for a safe thrust control (shaft rotational speeds, pressures and temperatures at various points along the gas path) the FADEC also monitors hundreds of various analog, digital and discrete data coming from the engine subsystems and related aircraft systems, providing a fully redundant and fault tolerant engine control.

mass airflow sensor

A mass airflow sensor is used to determine the mass of air entering the engine. The air mass information is necessary to calculate and deliver the correct fuel mass to the engine. Air is a gas, and its density changes as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the vehicle's operating environment, and is an ideal application for a mass sensor. (See stoichiometric, ideal gas law, and density.)

There are two common types of mass airflow sensors in usage on gasoline engines. They are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.

Both approaches are used almost exclusively on gasoline burning, EFI (electronic fuel injection) engines. Both sensor designs output a 0 - 5.0 volt signal that is proportional to the air mass flow rate, and both sensors have an IAT sensor (intake air temperature) incorporated into their housings.

When a MAF is used in conjunction with an exhaust gas oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the engine's ECU, and the EGO sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.

EURO V

EURO V is the most recent set in a series of mandatory European emission standards applying to new road vehicles sold in the EU. For heavy duty vehicles (lorries) the standards apply to vehicles brought on the market from October 2008. It requires Heavy Goods Vehicles (HGVs) to emit no more than 2.0 g/kWh of NOx and 0.02 g/kWh of PM. As yet, there is no Euro V standard applying for passenger cars, but a recent proposal suggests to limit diesel car emissions to 0.200 g/km of NOx and 0.005 g/km of Particulate Matter (PM), petrol cars to 0.060 g/km NOx and 0.005 g/km PM.

The standards do not mandate the application of specific technologies, but it is widely expected that diesel particulate filters will need to be fitted in diesel vehicles to comply with the PM standard.

Weber carburetors

Weber carburetors were originally produced in Italy by Edoardo Weber as part of a conversion kit for 1920s Fiats. Weber pioneered the use of twin barrel carburetors with two barrels (or venturi) of different sizes, the smaller one for low speed running and the larger one optimised for high speed use.

In the 1930s Weber began producing twin barrel carburetors for motor racing where two barrels of the same size were used. These were arranged so that each cylinder of the engine has its own carburetor barrel. These carburetors found use in Maserati and Alfa Romeo racing cars.

In time, Weber carburetors were fitted to standard production cars and factory racing applications on automotive marques such as Abarth, Alfa Romeo, Aston Martin, BMW, Ferrari, Fiat, Ford, Lamborghini, Lancia, Lotus, Maserati, Porsche, Triumph, and Volkswagen.

In the United States Weber Carburetors are sold for both street and off road use. They are sold in what is referred to as a Weber Conversion kit. A Weber conversion kit is a complete package of Weber Carburetor, intake manifold or manifold adapter, throttle linkage, air filter and all of the necessary hardware needed to install the Weber on a vehicle.

MegaSquirt

MegaSquirt is an aftermarket electronic fuel injection (EFI) controller designed to be used with a wide range of internal combustion engines. It is an open project headed by Bruce Bowling and Al Grippo, engineers that work on the U.S. East Coast. The project's do-it-yourself approach makes it the least-expensive system for this purpose. Basic costs are below US$200 as of 2005, although this can vary widely depending on application.

MegaSquirt is a successor of sorts to Bowling and Grippo's earlier EFI332 design, which was more complex yet more powerful system (at least initially). The EFI332 project started around 1995, and culminated in the release of about 200 kits in 2000. The system used a 32-bit MC68332 microcontroller from Motorola, hence the name. A steep learning curve is believed to have prevented the system from gaining wider acceptance.

The two engineers decided to simplify the design and focus on managing the fuel injectors (the EFI332 could also control the spark plug ignition system if so desired). The version 1.0 MegaSquirt used an 8-bit Motorola MC68HC908 microcontroller, but a later MegaSquirt-II upgrade included a 16-bit MC9S12. It is likely that a future version will use a 32-bit processor.

The assembled controller takes input from a few different sensors in order to manage the fuel injectors, including a throttle position sensor (TPS), exhaust gas oxygen sensor (EGO or O₂ sensor), MAP sensor, intake air temperature sensor (IAT), and a coolant temperature sensor (CLT). The latter two sensors themselves are usually the General Motors type, although you can recalibrate the controller to use other sensors.

There are several related projects, including:

• MegaJoltLite – an ignition system controller for the Ford Enhanced Distributorless Ignition System (EDIS)
• UltraMegaSquirt – an integrated fuel injection and ignition controller