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Comment by epistasis | Hacker News Reader

Gasoline engines are already 15% less efficient at 20F.

https://www.energy.gov/energysaver/fuel-economy-cold-weather

At -40F (-40C), it's generally good practice to just stay inside and not drive at all...

That 15% loss reduces your range from 1000km to 850km? That hardly affects how useful the vehicle is. For EV that’s different story.

How many vehicles have a 650 mile range? Almost none. Plus you can't fill up at home with gasoline, like you can with an EV.

> How many vehicles have a 650 mile range? Almost none.

'22 Ford Escape hybrid

The remaining miles thing shows less than that on a full tank, but I've been pretty consistently getting upper-600s between fill-ups.

I suppose it would probably be less if I went on the interstate more.

There's one. Go to a Car and Driver article about cars with extreme ranges, namely those over 650 miles, and they will start listing out particular years' models over a 10 year period in order to get to even ~10 models, and most of them are EcoBoost or variants or poor selling hybrid versions of other cars.

Assuming a 1000km range is a very strange thing to do, as it's a fringe feature that almost no one needs or wants! Recall that "almost no one" means that there's still some, an existence of a handful of people on HN is quite consistent with "almost none."

Of course I didn't pick it for range, I looked at price and miles of what the local carmax had and then separately looked up how tall the top of the windshield was.

Which I would expect to typically find something that's, um, fairly typical on characteristics I wasn't selecting on.

my 2010 F-150 with the notoriously terrible 5.4L gas engine seems to manage 1000km range. there's absolutely nothing efficient about it, it's just got a big gas tank.

Yep, Ford had to put really big tanks on even the F150 to make up for the horrid mileage. Even with a 36 gallon tank, when towing with an F150 you might only get 300 miles. It's one reason the Lightning had problems selling as many as they wanted (aside from the ridiculous pricing the first year or so). Most people who are serious about towing don't use an F150 anyway, but that doesn't mean that F150 buyers don't fantasize about their potential towing needs in the future.

Comparing range of gasoline cars is idiotic. There are plenty of cars with long range (1000km), and they all have 60L+ fuel tanks and most run on diesel (which gives you ~15% more range per liter). It'd even argue the same for BEVs. More battery is more range.

you can have drum of fuel enough for entire winter in your garage, the fuck you mean by "can't fill up at home"?

They mean that rounded to the nearest percent, 0% of people will be filling up their car at home from a drum.

rounded to nearest percentage zero people have winter-related car issues in the first place...

The point you are DESPERATELY trying to miss is you can easily "recharge", a "dead" ICE at home too

> The point you are DESPERATELY trying to miss is you can easily "recharge", a "dead" ICE at home too

Eh? All I can see is you DESPERATELY trying to push the narrative that it’s common for people have barrels of fuel at home which is a pretty weird thing to try and prove since everyone reading this will know it’s not true.

You mean EVs? Yeah, none that I'm aware of. But petrol/diesel cars? Loads of them. Even my 400bhp Volvo XC60 will easily do 650 miles on one tank of fuel. A diesel one will do 700-800. And a diesel Passat will go over 1000 miles on a tank without trying. Hell, even my basic 1.6dCI Qashqai could do 700 miles on its 55 litre tank

Volvo xc60 has an estimated 25 mpg overall (https://www.volvocarsrichmond.com/volvo-xc60-mpg.htm)

It has an 18.8 gallon fuel capacity (https://www.volvocars.com/lb/support/car/xc60/article/dfc6f0...)

That’s a max range of 470 miles. You would need much greater fuel efficiency above 34 mpg to get to 650 miles on an 18.8 gallon tank.

Cool, I guess when I did 700 miles on a single tank of fuel driving Switzerland to Italy and then again driving Italy to Austria and then again Austria to Netherlands this summer I just imagined it. My total for the 3000 miles was 38mpg(imperial).

Also you are quoting a value for the B5, which is not what I have, mine is a T8(and before you ask - no, I didn't have any opportunity to charge it anywhere on the way).

Every modern passenger car will show you 650 miles when driving at ~60mph. In the EU, anyway, and with a diesel engine.

90% of passenger cars in north america are gas powered

Not so in EU

> Gasoline engines are already 15% less efficient at 20F.

Is that actually true once the engine has reached operating temperature?

Short trips are worse:

> Fuel economy tests show that, in city driving, a conventional gasoline car's gas mileage is roughly 15% lower at 20°F than it would be at 77°F. It can drop as much as 24% for short (3- to 4-mile) trips.

The temperature difference should in principle increase thermodynamic efficiency. You get loss of MPG from other factors though mentioned in the link, like increased friction of moving parts, idling to warm up (0MPG), defrosters/seat heaters, lower tire pressure, denser air to drive through, winter fuel mixes which may not have as much energy, etc.

Once had a Porsche 914. Air cooled engine. Drove it across Montana and the Dakotas one winter. One very cold winter.

Not sure the engine ever reached "operating temperature" on that drive.

Sticking a piece of cardboard over a portion of the radiator was a common sight during the winter when I was growing up in rural Ohio. I didn't think our winters were that cold, but maybe late 70s to early 80s vehicles were more susceptible to running cold.

I had a car that developed a stuck-open thermostat and did the cardboard trick to get by until I could replace the faulty part.

I've had that happen, too, on a [more] regular car. I drove a Mustang 5.0 from Oklahoma to Oregon, and as I went through eastern Colorado the coolant temperature steadily dropped until it was resting at the bottom of the gauge. I don't recall whether the gas mileage suffered noticeably or not during that phase of the drive.

There are a bunch of things going on, and some people's measure of efficiency needs work.

1) winter blend fuels have less energy per volume, that doesn't make your engine any less efficient by energy but it does by volume of gas

2) lots of temporary cold effects: fuel vaporization, thick lubricants, etc. these things become less of a problem as the engine warms up but some energy is still lost on long drives

3) air resistance: all aerodynamic forces are linearly proportional with air density. At a constant pressure there's about a 15% difference in air density between the hottest and coldest places you can drive (and thus 15% less drag on a hot summer day than a cold winter day). aerodynamic forces are proportional to the square of your velocity and they become the largest resistive force around 50mph -- so at highway speeds you're losing efficiency because you have to push more air out of the way

4) energy used to maintain temperature: this is hard to calculate but some engine power is lost because the energy is used heating up the engine block and lost to the environment

5) the Thermodynamics 101 engine efficiency goes UP with increased temperature, but it's got a lot of real world effects to compete with, no spherical cows and all

Partial pressure variant fx on combustion outputs

Assuming you can get the car to start (mine needs an engine warmer at that temperature), it takes at least 15 minutes of driving to reach that temperature. Unless you’re going on a longer trip the engine most likely wont be warm by the time you reach your destination.

I had to drive in -30C once, the engine could not get up to final temperature after 2 hours of highway driving because I had to run cabin heater at full blast on windshield and side windows so they didn't cover with fog inside. But that was in very old low power car.

My tiny diesel car (2008 Toyota) needs its auxiliary heater below around -15 C for highway trips. It's a switch in my dash that burns extra fuel, otherwise the engine won't get up to or stay at temperate.

Pretty normal with diesel as it gives off less heat than petrol. I have a van with an 88kW engine, and even at -5c I can see the coolant temperature drop when I am idling down hill and have the heater on. Any colder and it's worth blocking the radiator with cardboard.

Protip for next time, cover the rad halfway with some cardboard and this will help a bit.

Garages exist though.

Schrodingers garage. Ceases to exists when talking about EV charging but exists when ICE vehicles need cold starts.

Heated ones are rarer.

I once had a condo with parking in a cave that was above freezing even when outside was -30 C (or F, close enough at that part of the scale). It was a great winter perk.

Well you have to keep it at operating temperature

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