What Does Your Car's 'Eco Mode' Do, And When Should You Use It?
Many modern cars have drive modes and they usually come with modes like "Sport Mode" and "Eco Mode". As the name suggests, the "Eco Mode" is short for "economical mode" and used when you need your car to be more efficient, especially in terms of fuel efficiency. When engaged, the car's ECU enacts some changes, and these changes differ between manufacturers, but they are more or less optimized to increase the efficiency of the engine.
When the "Eco Mode" is engaged, the car dulls down the throttle response of the vehicle. This means that the car might feel slower and it will only partially open the throttle to save on fuel even if you press the accelerator pedal more. This doesn't reduce the performance of the vehicle but rather smooths out the acceleration. Some cars also shift gears earlier. Some very advanced systems also reduce the power consumption by the air conditioning of the car. All these changes should help increase the fuel economy of your car.
As for when you should use it, it depends on the type of road you are driving. If you want to save on fuel, it is a good idea to switch it on and if you are going to do long boring highway miles, the "Eco" mode will help you with the fuel savings. You can also turn it on in the city, since you do not need to go very fast and a vehicle sips more fuel in slow moving traffic since there is a significant difference between a vehicle's highway and city fuel efficiency figures.
What If Your Car Doesn't Have An Eco Mode?
Many older cars do not come with driving modes which means that there is no Eco Mode either. But this is not a big deal because "Eco Mode" only makes your car efficient marginally and you can easily reek out similar benefits by driving smoothly and changing gears early. Even in most cars, the "Eco Mode" only alters the throttle response. You can yourself be light on the throttle pedal to achieve the same effect.
Other ways to increase your fuel efficiency is by using air conditioning on a nominal temperature. Opening your windows at higher speeds will cause more drag, thus reducing fuel efficiency so it is better to have it on. It is also important to have the right amount of air pressure in your tires, as recommended by the manufacturer. While cruising on the highway, you can quickly shift to the highest gear and use things like cruise control to keep a steady pace. A smoother driving style will help a lot more in some cases than having an "Eco Mode".