Question - could an E-turbo improve fuel efficiency?

[Cherokee]

How bout this for solid speculation from us arm chair engineers.
Rip that wimpy 2.5 Ltr out of the Mavbrid and slap it in the ass with the 2.0L Ecoboost.

I bet the first post related to my Idea will be why it will not work.
We landed on the moon in 69 remember?

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[AlsMaverick]

Even if it does, it likely wouldn't make financial sense to justify it. Sort of like folks that buy parts to improve aerodynamics and/or fuel efficiency (like tonneau covers). Yes, they will marginally increase fuel efficiency, but for a large up-front cost that'll take tens of thousands of miles to break even. Same with, say, replacing the tires with ultra-low-rolling-resistance ones. If you already need new tires, it's something to consider, but I wouldn't suggest replacing perfectly serviceable tires just in order to gain better fuel economy.

To maximize fuel economy, I suggest starting with what's free. Do a lot of 1-pedal driving, don't drive around with excessive stuff in the car, keep the tires properly inflated, keep the car washed, remove the spare tire and carry a plug kit and inflator, and so on. If you don't have back seat passengers, you could just remove the seat entirely.

Who buys tonneau cover for fuel efficiency?

 

[notfast]

Who buys tonneau cover for fuel efficiency?

Hopefully nobody, at least as the primary reason to purchase. I'm sure you can find plenty of studies that show that they do improve fuel efficiency, but it'd be like...replacing the steel wheels for alloy wheels. Maybe a 3% increase, but definitely not enough to offset the cost of the tonneau cover in a reasonable amount of time.

 

[commod0re]

turbochargers don’t really improve fuel economy in practice, they just increase displacement. E-turbos are no different in that regard; they just don’t lag, and have additional parasitic power draw on the vehicle

on paper they increase EPA estimates because EPA test procedures don’t engage the turbos as much as more typical driving conditions would. An engine with a turbo consumes as much or more fuel than a naturally aspirated engine that produces similar power. There’s really no way around that thanks to physics and chemistry. A given volume of gasoline only has so much potential energy in it… and the higher octane fuel that turbocharged engines crave actually has a bit less than standard gas, too!

 

[heady]

Currently the Chinese are the leaders in this space with a production gasoline engine from Geely sitting above 44% brake thermal efficiency on their 1.5L turbo miller cycle TGDI engine. https://www.sae.org/publications/technical-papers/content/2024-01-5107/

Breaking through 50% BTE is possible, but not really currently economical : https://ojs.sciltp.com/journals/ijamm/article/view/712 - in a nutshell:

The technological routes involve high compression ratios with optimizing geometric structures, implementing Miller cycles with VVT, utilizing intake boosting and novel combustion technologies for ultra-lean combustion (λ > 2.0), enhancing efficiency with thermal barrier coatings and low-friction lubrication, and ensuring reliable combustion through advanced diagnostics and control technologies.


However, issues related to material strength, emission control, cost, and reliability still require ongoing research and development.

High BTE can be accomplished at pretty much any engine size or power requirement, the 1.5L Geely plant is a little too small for a Maverick application as it's only about 135HP, but an engine with a bigger size and double the output for this larger application could just as easily have the same efficiency as that one does, if it were a priority.

 

[commod0re]

Another less obvious angle of doubt: turbocharging necessitates filling with more expensive, higher octane fuel, to get optimal efficiency and power, so even if it were somehow slightly more efficient, that’s overcome pretty easily by the extra 20% cost of the fuel itself

 

[inline_five]

The gas engine is the primary efficiency problem, so improving its efficiency, reducing the size of it and increasing the electric portion would improve overall efficiency and give the same or better performance. Switching to an Atkinson cycle has already been done in the Hybrid, so pulling even more efficiency gains within the gas engine are pretty questionable.

Reducing vehicle weight is another way to improve efficiency, both in acceleration improvements and in rolling resistance mostly from the tires. Its why you strip every non-essential part out of a racecar, even pickling the panels to cut their weight. This is why Ford went to a unibody in the Maverick and why the F150 is half aluminum instead of steel. Switching more Maverick panels to plastic or aluminum could probably pick up another 10% efficiency in the Maverick, but would obviously require the aluminum tarrifs to be removed.

Ignoring the pretend people who want to race, most people think performance is all about HP, but its really all about torque, especially in the low and midrange. That's why automatics with torque multiplication in the converter are quicker than manuals when you have more than enough engine (like a huge V6 or V8) to compensate for the large converter losses.

Think of Italian vehicles, where fuel costs 6 times as much, so efficiency is highly prized and as well you pay a very large road tax based on your engine size. The 500cc 2cyl Fiat can't haul what the Maverick can, but gets 100mpg without the addition of any torque from an electric motor and without the additional efficiency of the Atkinson cyle, and is a huge amount of fun to drive. It was never sold in North America because we don't like driving at 6,000rpm in normal traffic.

Toyota uses a smaller 1.8L engine with the same hybrid setup and the same eCVT to get them into the 60mpg area and roughly the same mileage city/highway. Ford with their bigger 2.5L engine cannot presently match that efficiency.

Prius is up to 2.0 nowadays, but their Cd is much lower than the Maverick as well.

 

[dochawk]

But to not ruin the Atkinson MPG, you'd only want the turbo at certain levels of power request - when the EV motors can't give enough or long enough,

The PowerBoost on the F-150 does this. It's able to completely hide turbo lag by using a lot of electric while the turbos spin up. (In fact, it has to only use partial electric, as the ICE & electric combined power would otherwise exceed what the 10R80 transmission can handle!)

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