Fuel Injectors

Fuel Injection is a method or system for metering fuel into an internal combustion engine. The fuel is then burned in air to produce heat, which in turn is converted to mechanical work by the engine. more...

In modern automotive applications, fuel injection is typically only one of several important tasks performed by an engine management system.

For gasoline engines, carburetors were the predominant method to meter fuel prior to the widespread use of fuel injection, however various fuel injection schemes have existed since the earliest usage of the internal combustion engine.

Prior to 1980, nearly all gasoline engines used carburetors. Since 1990, almost all gasoline passenger cars sold in the United States use electronic fuel injection (EFI).

The functional objectives for fuel injection systems can vary. All share the central task of supplying fuel to the combustion process in the engine, but it is a design decision whether a particular system will be optimized for power, fuel economy, low emissions, special fuels, durability, smooth behavior ("driveability"), or other objectives. Because some of these goals are conflicting, it is impossible to optimize a single system for every goal simultaneously. For example, maximizing fuel economy or power comes at the price of somewhat higher exhaust emissions. In practice, automotive engineers strive to provide an all-round blend of competing goals to best satisfy customers, all while complying with emission regulations.

An EFI system costs more than a carburetor system, but a greater number of the competing objectives can be better optimized with EFI than a carburetor.

Benefits

An engine’s air/fuel ratio must be accurately controlled under all operating conditions to achieve the desired engine performance, emissions, driveability and fuel economy. Modern EFI systems meter fuel with great precision, and when used in conjunction with an Exhaust Gas Oxygen Sensor (EGO sensor), they are also very accurate. The advent of digital closed loop fuel control, based on feedback from an EGO sensor, permit EFI to significantly out perform a carburetor. The two fundamental improvements are:

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