Some vehicles require engines to be built inside them in order to run. There are a number of different types of engines, used in different vehicle types.
Engines will accept fuels just like any other storage device. The amount of fuel consumed during travel is determined by the following equation (where "**" means "raised to the power of"):
fuelusage = engine * (vehicle_minimum + ((vehicle_maximum - vehicle_minimum) * (current_speed/maxspeed)**6))
engine = engine usage factor for the fuel type (defined for each engine type)
vehicle_minimum and vehicle_maximum = usage variables that are defined for each vehicle
Fuel injection system
A fuel injection system (FIS) increases the efficiency of one specific type of fuel, while preventing others from being used. Existing engines must be removed and a new one installed together with the FIS.
Below is a list of types of engines that can be made, organized as they are listed in the in-game manufacturing menu.