I don’t understand what is different that prevents cars from starting right up in cold weather. Fuel is present, air is there..spark plugs are …sparking ..and as long as you have a strong battery the starter is turning the engine…why the struggle?
In: Technology
Batteries are powered by chemical reactions that make an electric current as a product. Most chemical reactions occur much slower in cold temperatures. Slower reaction = less electricity generated per second. Less electricity per second means your car can’t make enough sparks to ignite the fuel in your engine, which means it can’t start.
If you have a strong battery, these effects are small, unless you’re in like, *really, really* cold weather.
**Edit:** Another user pointed out that sparkplugs don’t actually carry the current to the engine to make it start. That’s done by a separate motor carrying an inrush current. It’s still an issue with current, just not with sparkplugs
**Edit 2:** Those claiming that engines won’t start at low temps because of oil being more viscous or that moving solids are packed closer together and introduce friction as a result aren’t *completely* wrong, but it’s not the primary reason for this occurrence. The density of a liquid or solid (such as motor oil or the metals used in your engine) does change with temperature, but the scale at which this occurs is not enough to prevent your engine from starting (at least for the majority of cars on the road). It is enough, however, to increase the amount of work required by your engine to do its job, which would increase the current needed to start your engine. You’ll also have lower gas mileage when your engine is cold vs warm for the same reason.
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