An engine control unit, sometimes known
as a power train control module or as an engine control module (though there are
definite differences), is a device that regulates and maintains certain key functions in your
It determines things like the fuel injection,
ignition timing, and other things. These are all very important functions that must be accurately
commenced in order for an internal combustion engine to run appropriately.
The way that the engine control unit knows what to
do is by reading data input from sensors. These sensors monitor the engine, and send information to
the ECU so that it knows things like how much fuel is needed, etc.
Before the invention of the ECU, things like fuel injection, idle
speed, and even ignition timing were controlled mechanically, or by pneumatic sensors. These worked alright, but
engines have gotten a lot more reliable and trustworthy since the advent of the ECU.
Some examples of how the ECU will control engine functions might
be in the case where an engine is not completely warm yet. In this case, the ECU will receive information regarding
the temperature of the engine, and will inject more fuel into it to keep it running smoothly.
Then, once the engine warms up, it will taper off the amount of
fuel, causing it to run more efficiently. Another example of what the ECU does is control the spark. It can sense
the exact moment where spark is needed, and will fire the spark plugs accordingly so that the fuel will be
If the engine is knocking, the ECU will delay the timing of the
spark plugs to get rid of it, thereby preventing engine problems in the long run. Knocking can damage an engine,
and the ECU in your vehicle is designed to prevent this from happening.