Fuel consumption. Summer vs Winter

[Bendy toy]

Cold air should make the engine more efficient, but it will also over-cool an aircooled engine so its likely to run richer in winter.

Time for some engine socks maybe.

 

[Deleted account 190920001]

I think the main cause is not friction.

Cold air is more dense and hence contains more oxygen. This is detected by the sensors and fuel injection allows more fuel to be injected, to obtain the same fuel/oxygen mixture for optimal combustion.

So cold weather means more fuel AND more power. You should also notice that your bikes pulls stronger in cold condions. Which is a shame of course, since we don't want more power when tarmac & tyres are cold and there may be ice or snow around.

Humans are habitual. We tend to drive the same instinctively and doing x will require the same amount of power, air/fuel, whether the air is more dense or not. You will open the throttle to what feels the same to you. Couple that with the fact that you generally don't drive as hard in the cold and wet you should actually see a reduction in fuel consumption.

Your theory although technically correct doesn't really explain increased fuel use in cold weather.

 

[alex_rsa]

The summer winter difference is actually worse then I thought. Rememeber my ride is identical (except for the vagaries of traffic) and I ride at the same speed.

Winter - ran out twice under 190 miles (my tank holds 23 lt when totally empty) so roughly 37mpg

Summer - 205 miles on 21 litres so 44.4 mpg

I do use a different tyre in Winter which will explain some of the difference and there is extra drain on the battery for heated grips but would that explain 20% difference?

What sensor is actually used by the ECU to check if the bike is up to temperature?

 

[ianf]

Don't they adjust the formulation of fuel on a summer/winter basis here?

 

[Deleted account 190920001]

Don't they adjust the formulation of fuel on a summer/winter basis here?

They definitely do with diesel, not sure about petrol though. I can't think of a reason why to change petrol but there might be.

 

[Dakbutler]

I used to work on forecourts a lot, on the equipment side not the technical side of making fuel, and I'm pretty sure, although not certain, that I heard talk of different fuel compositions in the winter and summer.

I think it was to do with the amount of LPG blended back into the fuel (as LPG is by-product of petrol production, they want to get shot of it).

Also petrol is more dense in the winter, so 20 litres of fuel in the winter has more calories than 20 litres in the summer - but of course that would produce the oposite effect.

However in the underground storage tank it tends to vary by only a few degrees from mid winter to mid summer (the tank depth averages about 10 feet - that's 3m for those too young to remember VHS), but of course a bike tank is VERY exposed - so you fill the tank with toasty petrol, and then refrigerate it during your journey, hence it shrinks.