Without abandoning piston engines entirely and going to turbines or something, modern auto engines are approaching maximum practical thermal efficiency for the conditions under which they must operate (being primarily horsepower-oriented rather than torque-oriented). You can get maybe 50% better if you're powering an oil tanker rather than a car, but you're not powering an oil tanker, but rather something that has to accelerate and decelerate and idle in unpredictable ways.

Hybrid was the last big improvement. Barring a radical new technology (and variable valve timing ain't radical), we might squeeze, what, 10% better thermal performance out? Get 40mpg rather than 37? Big deal.

And really, this is all driven by energy costs in the end. We're already hitting a point where commodity solar/wind electricity is cheaper than commodity coal, and much cheaper than commodity gasoline. This creates a tremendous market incentive for purely electric vehicles. And that tech has much more room for improvement than any gas engine - batteries will keep getting cheaper and more efficient for some time to come.

When my options are a $25,000 Ford or a $90,000 Tesla, an electric car seems like a dream. But when it turns into a $25,000 Ford or a $30,000 all-electric car (maybe from Ford!)... TCO starts becoming a very attractive argument, on top of the feel-good factor.

"This creates a tremendous market incentive for purely electric vehicles."

Can confirm. I bought a used Nissan Leaf two months ago from a dealer (being used it was a small fraction of the $25k Ford). A near-identical car (trim/mileage/colour) is now listed on their site for close to 30% more than I paid.

If we were living in normal times this would make no sense - but the TCO picture is changing that rapidly (owing to oil prices going up and used EVs being so scarce).

I paid $5k for my 2011 Leaf with 10 bars and 30k miles. Best decision ever. Seems like people are catching on though since theyre getting hard to find anywhere near that now.

Well.. these people you speak of can find their own.

Something something cold dead hands, etc.

We still have to see how HPPI and turning off two cylinders out of four at low speed improves fuel consumption. There are also alternative fuel options for ICE vehicles such as LPG for petrol powered vehicles and DME for diesel vehicles. Current diesels already do 65 mpg which is a big deal compared to 36 mpg. DME can be produced locally out of syngas from industrial processes or biomass.

Regardless, an all-electric car is going to be pushing 90% thermal efficiency - transforming energy into acceleration. A combustion car isn't going to break 40%. Exotic tech like variable timing and taking cylinders out of service isn't going to get huge gains - they're actually a lot of work for tiny gains, because all the huge gains have already been had. Moreover, electric cars will get that efficiency with no compromise in performance, unlike combustion cars with tiny, weak, "fuel efficient" motors. A Tesla Model S is the fastest car in its class, as well as the most efficient.

The only big win for combustion-based cars is the range potential, because the energy storage of liquid fuels is so much denser. I don't expect to see electric commercial aircraft in my lifetime. But biomass-based liquid fuel? Sure. It just won't be cost-competitive with solar/wind into a battery. It'll be limited to specialized applications where power/weight matters.

That's simplified as an engine + exhaust system + gas tank + gas + transmission weighs hundreds of pounds more than an electric cars engine alone. Electric cars do weigh more, but the difference is not that massive.

You can actually drive further using gasoline to turn a gas turbine > electricity > electric cars battery than using that same fuel to operate a normal IC car. But, nobody does that because wind/solar/coal/nuclear are all far cheaper than gas.

Plug in hybrids are probably only viable for a particular range of battery costs. When batteries are expensive it’s worthwhile reducing that cost by spending the extra money on a duplicated drive-train. As the cost of the battery falls the savings by having the extra drivetrain complexity fall.