83 Volvo LCP2000, 56 mpg city/81 highway
 

It’s called a Light Component Prototype because the goal was to make the car from components that were, well, light. Plastics, magnesium, and aluminum were used, selected for their light weight and recyclability, and carbon fiber was even used for the door frames, which was a huge deal back in 1983. The entire floorpan of the car was a single plastic piece, to which the rest of the body was attached.

The result of all these novel materials is that the car weighs under 1600 lbs!

The drivetrains were interesting, too; two options were developed, both three-cylinder turbodiesels: one 1.3-liter magnesium engine that made 50 horsepower, and a cast-iron 1.4-liter engine making 90 hp. Heat-insulated without a cooling jacket in the cylinder head and using the engine oil as coolant instead. It ran on any oil fuel, like rapeseed oil, which gave the car a nice smell of fish & chips when it drove past. All LCPs had front-wheel drive, and either a five-speed manual transmission or an electronically controlled CVT.

The combination of the light weight, CVT transmission (which Volvo got from their purchase of DAF), and efficient turbo diesel engines meant that the LCP2000 got 56 MPG city/81 highway, which is as good as a Prius in the city, and way the hell better on the highway.

Full story with pictures:this-1983-volvo-concept-would-have-been-a-much-better-prius

Very interesting. Thanks for posting.

Those engine configurations sound quite like that Elko Multifuel "semi-adiabatic" engine that had been tested even here in Brazil during the 80s.

What a cool car did it ever go into production?

No but the naturally aspirated Daihatsu Charade diesel was produced and did get the same fuel economy metrics

Except the claims comparing mileage to the Prius are based on different standards. Saying this prototype gets 84 highway or whatever is the same thing as the Elio claiming the same thing. Put it in through a modern day EPA cycle the Prius is rated on and I doubt it beats it. Also now add modern crash standards and emissions and I doubt it beats a Mirage.

Just for comparison the 2017 Cruize diesel gets 77mpg on the old style highway EPA test and that still includes acceleration and deceleration. Put the Cruize at steady state 55mph speed limit on 1982 and I bet it beats the 81 mpg with modern emissions and safety. And you can buy it!

The Daihatsu Charade diesel was claimed to be a 100mpg at 55mph car.

It was even highlighted in a mileage challenge in the 1980's

Anyone but a US citizen can buy one

That option was also not available here in Brazil when the Charade was briefly available locally, even though I have already seen it in Uruguay. But anyway, comparing that Volvo prototype to modern hybrids and econoboxes, it still seems quite smart due to the ability to run on roughly every fuel due to the semi-adiabatic engine. And probably water injection could easily address the emissions issue.