This means that they save energy and therefore are "fuel savers". Indeed, with standard engine oil, in urban driving or when starting the engine, approximately 40% of the energy is consumed by the vehicle as the result of engine friction. Fuel Economy lubricants contain special additives that are used to reduce the friction responsible for energy losses and engine wear. With a fuel economy lubricant, the engine does not need a lot of energy to start, therefore using less fuel (reducing CO2 emissions) and improving the engine lifetime of your vehicle.