ECU

An Engine Control Unit (ECU) is any microcontroller used to control an Engine, usually a Modular engine.

Engine throttle is often controlled using a PID Controller, although other controllers may be used if desired.

Modular Engines

A modular engine ECU automatically calculates the required air and fuel throttle values, as controlling the starter motor and sometimes also the clutch.

For non-Supercharged engines, the fuel throttle must always be half of the air throttle. The function f(x) = clamp(x/2, 0, 0.5)can be used for this purpose.

Supercharged engines require fuel throttle to be dynamically calculated, such that the air to fuel ratio remains the same.

Many ECUs have automatic shut off systems to prevent the engine from overheating.