Anengine control unit (ECU), also called anengine control module (ECM),[1] is a device that controls various subsystems of aninternal combustion engine. Systems commonly controlled by an ECU include thefuel injection andignition systems.
The earliest ECUs (used by aircraft engines in the late 1930s) were mechanical-hydraulic units; however, most 21st-century ECUs operate usingdigital electronics.
The main functions of the ECU are typically:
The sensors used by the ECU include:[2]
Other functions include:
In acamless piston engine (an experimental design not currently used in any production vehicles), the ECU has continuous control of when each of theintake and exhaust valves are opened and by how much.[3][4]
One of the earliest attempts to use such a unitised and automated device to manage multiple engine control functions simultaneously was created byBMW in 1939Kommandogerät system used by theBMW 801 14-cylinderradial engine which powered theFocke-Wulf Fw 190 V5 fighter aircraft.[5] This device replaced the six controls used to initiate hard acceleration with one control, however the system could cause surging and stalling problems.[citation needed]
Despite its limitations, the Kommandogerät represented a significant step toward integrated engine management by mechanically linking throttle position to fuel delivery, ignition timing, supercharger control, and propeller pitch. The system used cams, gears, and pressure-based regulators to compute appropriate settings across different operating conditions, effectively acting as an early analog computer. Although it lacked the adaptability and precision of later electronic systems, the Kommandogerät demonstrated the feasibility of reducing pilot workload through automated coordination of multiple engine parameters. Its underlying concept influenced subsequent developments in aircraft and automotive engine control, eventually leading to electronically controlled systems such as full authority digital engine control (FADEC) and modern engine control units (ECUs).[6]
In the early 1970s, theJapanese electronics industry began producingintegrated circuits andmicrocontrollers used for controlling engines.[7] TheFord EEC (Electronic Engine Control) system, which used theToshiba TLCS-12 microprocessor, entered mass production in 1975.[8]
The first Bosch engine management system was theMotronic 1.0, which was introduced in the 1979BMW 7 Series (E23)[9] This system was based on the existingBosch Jetronic fuel injection system, to which control of the ignition system was added.[10]
In 1981, aDelco Electronics ECU was used by severalChevrolet andBuick engines to control their fuel system (a closed-loop carburetor) and ignition system.[11] By 1988, Delco Electronics was the leading producer of engine management systems, producing over 28,000 ECUs per day.[12]
Such systems are used for many internal combustion engines in other applications. In aeronautical applications, the systems are known as "FADECs" (Full Authority Digital Engine Controls). This kind of electronic control is less common in piston-engined light fixed-wing aircraft and helicopters than in automobiles. This is due to the common configuration of acarbureted engine with amagneto ignition system that does not require electrical power generated by analternator to run, which is considered a safety advantage.[13]
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