February 24, 2010 Vol. 6, No. 4
What do you think of when you read or hear ‘Switzerland’? Maybe you think of watches that cost as much as a small car, but mountains probably come first, right? Those pristine soaring peaks that usually rich and maybe brave people climb up or slide down. You might also think of big, slurpy, friendly dogs that will rescue you when the climb or the slide goes ovaloid and leaves you temporarily buried below 73 feet of pure, white snow. And then there’s the chocolate that can melt away all such cares after you’re once again sitting by the fire in your two-grand-a-night chalet, drinking the brandy you stole from around the mutt’s neck.
All those things scream Switzerland. ‘Turbocharger’ doesn’t.
But you’re going to have to add it to your list of Swiss images because that’s where turbocharging drew its first breath of air, if you’ll pardon the pun. That was in 1909 or so, and it seems Swiss truck maker Saurer first sold a turbocharged diesel truck way back in 1938.
All this arises because there’s been a discussion both in e-print and behind the scenes here about the origins of turbocharging in heavy trucks. I asked for reader input and got it, and then I went for a bit of an online search — man, I love the Web — to pin things down a little further. Believe it or not, that even took me, quite by unpleasant surprise, to the website of a Holocaust ‘revisionist’, or denier in more common parlance. I’ll say no more on that one.
Predictably, I suppose, I found turbocharger histories that purported to be factual but were in fact highly proprietary, little more than promotion for a given company’s wares. I found errors and maybe lies and more confusion than I expected. So while I sure do love exploring things online, I was reminded yet again that the gospel truth ain’t always the real truth.
Oddly, I also got the impression that the difference between supercharging and turbocharging isn’t always well understood. Just to get things straight, both of them increase an internal combustion engine’s power by throwing a lot more air into the mix than natural aspiration can manage. While a supercharger is driven by mechanical means — a belt or a shaft or some such — a turbocharger is an exhaust-driven pump and it’s generally a fair bit more efficient. The other key difference is that you get instant response from a supercharger but, as you well know, you have to wait for a turbo to spool up.
The first instance of a supercharger I could find was in 1860, in Indianapolis, the invention of a guy called Francis Roots, though his gizmo wasn’t patented for an IC motor until Gottlieb Daimler of Daimler-Benz did it in 1900. Roots ‘blowers’ subsequently became pretty common.
Not long afterwards, somewhere between 1909 and 1912, according to the useful Cummins Holset U.K. website, a Swiss dude named Dr. Alfred J. Büchi developed the first exhaust-driven supercharger. He was chief engineer of Sulzer Brothers Research Department, that company being engaged — since 1834 — in making railway locomotive engines. Apparently he proposed a turbocharged diesel engine at the time, but nobody listened.
This tale could go on and on and I’d better hold back here, but one interesting side note is absolutely required. Sulzer spun off its diesel engine division in 1990 to a Finnish outfit called Wartsila, which now makes the world’s biggest reciprocating engine to power those huge container ships. The basic specs are astonishing…
The biggest version of that two-stroke diesel engine, the RT-flex96C, stands five stories tall and its 14 cylinders produce — get this — 114,800 hp. It gets better: the thing spins out 5,608,310 lb ft of torque at a mind-blowing 102 rpm. Yes, 5.6 million lb ft at 102 rpm.
And you think you have fuel-economy problems? Try 3.8 litres a second for this giant.
Getting back to the task at hand, it seems the first turbocharged diesels in commercial use were 2000-hp Sulzer types powering a pair of German ships in 1925. By the 1930s they were getting common in ships and locomotives and stationary applications, with Dr. Büchi licensing manufacturers in Europe, the U.S., and Japan.
Now things start to get a bit murky. One of my readers, a Swiss fellow, submits that Swiss truck-maker, Saurer, was first to sell a turbo-diesel truck (see the pic here). An online history of Saurer agrees with him, saying the year was 1938, but I can’t yet find a pile of corroborating evidence to suggest that it was widely sold.
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