I noticed my car burns more fuel in winter. I don’t use the heater or Air Con. So all being equal why more fuel? Is it something to do with Oxygen density in cold weather? If so, please explain 🙂
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Your car automatically adjusts your fuel to air mixture to be at at optimum level to balance power and economy. When the air is cold, it is more dense (essentially there is more air in each cylinder) so you need more fuel to reach that same balance point.
In a lot of small aircraft they don’t have automatic mixture control, you do it yourself with a pull knob. The difference in the optimal position of the mixture on a very cold day vs warm one in the summer is quite significant.
Was no one going to mention that winter gas has a different formulation than summer gas? Winter gasoline is formulated to evaporate easier than summer gas. The more volatile fractions in winter gas have less energy so summer gas gets better mileage.
It takes longer to get to operating temperature. The coolant temperature sensor tells the computer to make the fuel injectors spray more fuel when the engine is cold.
Air is more dense, takes more energy to push through. it will have more and more impact as speeds get higher.
Winter tires are softer and more aggressive. Good for traction, bad for fuel economy.
Snow and slush take more energy to push through.
Even spinning your tires at an intersection while trying to get going is taking energy that’s not going into forward momentum.
Edit: Also, when left outside all fluids/oils cool off and become more viscus. It takes more energy to push them around or rotate shafts in them until they warm back up.
The main cause is air density. Colder air is denser, which means it is thicker and causes more drag. So, the car has to deal with more drag, and you need more fuel to maintain the same speed and acceleration.
There are some other effects, such as the engine and powertrain taking longer to warm up – so there is more friction from cold parts and cold oil. If you do shorter journeys, this becomes more significant, and for very short in-town journeys, this could be the main effect.
Do you live somewhere that uses oxygenated fuel in winter? Ethanol is added to the fuel and that causes a small reduction in fuel economy.
What vehicle do you have? Type of propulsion?
Cold air should help a internal combustion engine, not the opposite.
The only reason I can imagine is: driving on snow or water or mud makes more resistance than dry tarmac.
Second if you have a hybrid car, batteries are heated because they can’t handle cold temperatures. If you have an electric or hybrid car, it will use some power to heat the batteries in winter and that has a negative effect on consumption. This is more marked on short commutes, given batteries are heated in the very first minutes of use.
in the cold weather tires loose some air. make sure you drive with the correct tire pressure. driving with lower pressures will impact fuel comsumption.
Why don’t you use the heater? It shouldn’t affect fuel economy like ac does, and ac is more efficient than wind drag in the summer at highway speeds.
Warming up the car also uses some fuel, and you should be doing that.
A few reasons:
-Air density, winter air averages about 10% denser than summer air, so more fuel goes in with it.
-Winters on average have stronger winds, meaning more aerodynamic drag.
-Colder parts in the powertrain makes more friction, meaning some additional loss of power efficiency.
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