100 mpg engine in the making.

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Mcdowell's Sterling engine is claimed to be, at peak, 50% efficient. That's considerably better than the current Prius, which reaches 40%, and Toyota's next gen hybrids which reach 41% thermal efficiency coupled with higher output.

FYI, VW's diesels are nearly 43% efficient.

But that won't get a normal sized car to 100MPG. Consider the diesel, at 43%, achieved just over 40MPG on more energy dense diesel fuel. The current 40% efficient Prius with hybrid drive reaches 55MPG in real world use. A 20% improvement would mean MPG's in the 60's.
 
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MacDowell obtained a Stirling engine from NASA. The space agency experimented with one in several vehicles during the late 70’s & early 80’s and got roughly 54 miles per gallon in a Dodge pickup.


Wow.

Article also says he believes the automotive industry will be beating his doors down.

I think it more likely they'll slip quietly into his bedroom in the middle of the night.
 
VW built a prototype diesel three cylinder in the 80's that delivered over 175 MPG its never been put in a production car they made no effort to market it.
 
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Originally Posted By: DoubleWasp
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MacDowell obtained a Stirling engine from NASA. The space agency experimented with one in several vehicles during the late 70’s & early 80’s and got roughly 54 miles per gallon in a Dodge pickup.


Wow.

Article also says he believes the automotive industry will be beating his doors down.

I think it more likely they'll slip quietly into his bedroom in the middle of the night.
and the automotive industry won't look him square in the eye the following morning and say "you should take me to brunch!", either!
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In the UK in the 1970's Ford managed to make a 100mpg (Imperial - more like 80mpg in US gallons) with an unmodified - but I suspect blueprinted - 1100cc Escort model. The car had everything removed from the interior that wasn't necessary for driving it, the transmission was a direct coupling to the rear axle, no gears to add drag. front brakes removed, and skinny tires inflated to around 100psi. It was driven round a flat circuit at something like a constant 30mph, it was just to show what could be done.
I could get 65mpg from my 1.0 liter Nissan driving it very gently on open roads.
Vehicles have been built that have returned 1000 mpg, by various university engineering colleges.
We are still many years away from a realistic 100mpg family sedan though.

Claud.
 
My brother was working on a 100mpg engine in the Sloan Engine lab at MiT when he was there. Now it was achieving this under lab conditions at 72F but it is impressive for a 4 cylinder to put out the same power and achieve that kind of mileage on the highway (simulated).

It was neat to see them capture all the exhaust emissions in a special bag and then feed it to an analyzer.
 
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100 mpg in what?. It's conceivable that a micro car such as a VW up or something the size of the original Mini could be a realistic proposition soon. But a Honda Civic or Ford Focus size car?, or anything that meets current safety regulations?. not anytime soon imo.

Claud.
 
It was a modified Ford 4 cylinder. Engine was from Europe and had a 2L displacement roughly. They were also working with laser type experimental ignition systems because of increased combustion efficiency due to the way it would ignite the fuel.
 
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How can a car get 100 mpg unless it is something like the old BMW Isetta's. If we are going back to the isetta's I don't want a car a gorilla can throw to the other side of town, and not even manage to seat two comfortably.
 
Given how many years ago this was posted it likely isn't feasible, typically a sterling engine takes a long time to heat, weighs a lot and is designed for continuous low power output.

I doubt much has changed


Also if a car were offered that gets better gas mileage they would tax the crap out of it so you don't save any money,

oh wait they already do that.
 
Originally Posted by billt460
Originally Posted by mightymousetech
Most companies have pretty much stopped developing newer gas engines. We will be full electric soon enough.

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By the year 2525
 
Originally Posted by Shannow
100MPG by definition requires that a gallon, 44.8hp hr is your entire energy budget for the distance.


This is the correct answer.

For those who don't understand, one gallon of gas contains (the energy equivalent of) 44.85 horsepower for one hour. If you could use gasoline at 100% efficiency, you would be able to produce 44.85 horsepower for one hour.

Interestingly, the Prius engine at 41% thermal efficiency can produce 18.4 HP for one hour on a gallon of gas.
 
Opposed Piston + hybrid technology + using UK mpg instead of US mpg should be able to hit 100.

A car needs what, 20hp to be propelled down the highway at 60mph, so a 50% thermal efficiency engine should be good for an hour and a half or so on a gallon of diesel (20-30% more energy content, BTW), and if you adjust the gallon to UK gallon, voila, 100mpg.
 
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