What happens when your nation is going through an oil crisis, but you want to keep building big-ass land yachts? You just crush up some of America’s plentiful coal supply, and use that to move the barge down the road, I guess.
Chrysler’s three decade-long turbine program tends to get all the credit, but GM had its own nerdy engineers looking at turbine power as far back as the 1950s. Fast-forward a few decades from then to the second oil crisis in 1979, and the General decided to use that expertise to build alternative-fuel turbines— particularly, ones that ran off powdered coal.
Two coal-fed turbine cars debuted in the early 1980s, a 1978 Cadillac Eldorado and the 1977 Oldsmobile Delta 88 you see in the Motorweek video above.
The way they worked was very interesting. As The New York Times mentions, under the vast hoods of these cars was a coal bin, whose powdery contents had to be “agitated” by what the Christian Science Monitor referred to as “mechanical vibrators.” The New York Times goes on to quote a GM engineer who worked on the project named John Schult, who said a “small conveyor belt delivered the coal [from the bin] to the gasifier,” and that compressed air then “blew the coal from the conveyor into the gasifier.” He went on, saying:
When you stepped on the gas pedal, it actually moved a potentiometer that varied the speed of the coal conveyor belt. More fuel resulted in more power.
He mentioned that the car had considerable power lag thanks to the clunky fuel delivery system, but that once the engine did get going, the car got out of the hole really quickly.
To get the car started, Schult told The Times, the engine used diesel fuel to commence the combustion process, but once that was done, the turbine engine automatically switched its fuel source to coal, a process that an earlier New York Times article says involved diverting the compressed air to the fuel tank “to keep the coal powder flowing, like a liquid, into the combustion area.”
Talking of the sound of the strange contraption, Schult said:
The sound was unique, that characteristic whine of a jet engine. And then there was the constant high-frequency buzz of the agitator that kept the coal dust ready for delivery, overlaid with the noise of the compressed air system that blew the coal from the conveyor into the gasifier. It didn’t sound anything like a regular car engine.
In the earlier 1981 article on the topic, the newspaper quotes GM’s vice chariman Howard Kehrl as saying the vehicles would be “products of the next century.” But we’re already in the next century, and coal turbines are nowhere on the radar; clearly, this was a big PR stunt.
The tech’s failure was the result of a number of drawbacks. The New York Times says that despite being coal, the messy fuel— whose dust particles averaged three microns in diameter— just wasn’t commercially available. On top of that, emissions were a major problem due to coal’s high sulfur content and impurities. In addition, The Times wrote, the “inert ash must be reduced to avoid fouling the engine.” Albert Bell, head of coal car project, told the newspaper that:
Mechanical ‘’cleaning’’ of coal emissions could add 67 cents to the cost per million B.T.U.’s, while the more effective solvent cleaning system would add $2.80.
So, add the clunky fuel delivery system (with a conveyer belt!) that yields laggy throttle response, filthy emissions and fuel that’s hard to come by, and you’ve got an idea that just ends up being a “neat” speck on the timeline of automotive history.
But I, for one, am glad that speck is there.