An Engine is an essential component of a car, providing power to its wheels and accelerating it.
In Automation, engines are designed by players with a more or less broad application in mind. The applications range from small, fuel efficient engines required in a city car, or robust and reliable pickup engines with a supply of low-end power, to smooth high-end engines with enough power to propel a luxury car, or high-performance sport engines. Understanding how to build an engine suitable its application greatly aids the player's ability to design high-quality cars.
Engine Family vs Engine Variant
Engine Family is a term describing engines sharing the core design choices. The members of the Engine Family, which can have differ in non-core design choices, are Engine Variants. Engine Variants of one Engine Family can be produced on a shared production line. Because of this, keeping the number of Engine Families to minimum can be a good way of minimising the running cost of the company. However, since the core design choices are shared, the Engine Family can limit the range of applications its variants may be suited to, more or less severely. (For an instance, a large-sized V12 family's variants will most likely be only suitable for top-trim luxury cars, or top-tier performance vehicles)