The World’s Largest Internal Combustion Engine: A Walk Through The Inside Of The Wärtsilä-Sulzer RTA96-C Marine Engine

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(first posted 2/6/2014)    How’s that for a truck with a big engine? Actually, that’s just an eight-cylinder version of the Wärtsilä-Sulzer RTA96-C; they also come in bigger multiples of cylinders, all the way to fourteen. Want to guess how much power it makes? Hint: in the six figures. How about a walk through?

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Let’s take take a look at what makes these giant marine engines work, and work they do, powering the many giant container ships. The largest version, with 14 cylinders, was first installed in the Emma Maersk, and makes 108,920 hp @ 102 rpm, and a planet-rotating 5,608,312 ft/lb of torque at the same speed.

These are real “strokers”, cylinder bore is just under 38″; stroke is a mammoth 98″. That makes for 111,143 cubic inches (1820 L) per cylinder, for a grand total of 1,556,002 cubic inches (25,480 L) for the 14-cylinder version. And it takes some 1,660 gallons per hour to keep it fed. But it’s extremely efficient, exceeding 50% thermal efficiency, roughly twice of typical automotive engines.

These engines are two stroke diesels, with uniflow-exhaust scavenging, essentially similar to the famous two-stroke Detroit Diesels. The have intake ports openings in the cylinder barrels, and the spent gases exhaust via valves at the top of the cylinder head, actuated hydraulically.

Similar to steam engines of yore, these engines have a sliding cross head, so that the piston rod travels only vertically, thus avoiding loading the piston with any lateral movement.


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Here’s the crankshaft for a ten-cylinder engine. Note the built in “ladders” to climb down into the base of each crankcase “cellar”.

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Workers are inserting the crank bearings. The crank and journals are 38″ in diameter and 16″ wide.

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A piston and piston rod assembly. The square base is what connects to the cross head assembly.

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A ten cylinder engine awaiting the attachment of its final cylinder. The cylinder liners are die-cast ductile cast iron. Those cylinder bolts look they’re up to the job. This factory is in obviously Korea.

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The first 12 cylinder engine completed.

Big diesels aren’t exactly new; here a video of what was once the world’s biggest diesel engine in 1932, a generator in Copenhagen, DK. It produced 22,000 hp, and is still operational, as this video shows.

images and some info from