Designed to power giant container ships, the 14-cylinder Wärtsilä-Sulzer RTA96-C two-stroke turbocharged diesel engine is the world’s largest combustion engine.

Measuring thirteen meters high, twenty-six meters long, and weighing a whopping 2,300 tons, the 14-cylinder Wärtsilä-Sulzer RTA96-C is a metal monstrosity worthy of the title of ‘largest combustion engine ever built’. The giant crankshaft alone weighs 300 tons, while each of the 14 pistons weighs 5 tons. At 102 rpm, it has a power output of 108,920 bhp (80,080 kW) and burns through about 250 tons of heavy fuel oil per day. Even at its most efficient setting, the enormous Wärtsilä-Sulzer RTA96-C consumes 1,660 gallons of heavy fuel oil per hour.

Finnish engine manufacturer Wärtsilä decided to build the world’s largest combustion engine when it became clear that its 12-cylinder RTA96C engine wouldn’t be enough to power ever-larger container ships like the Emma Maersk efficiently. Only instead of building it from the ground up, it merely extends the engine power range of the tried-and-true RTA96C engine to 80,080 kW by adding a couple of extra pistons.

Simply adding extra pistons wasn’t a decision taken lightly, as the company had to ensure that the engine ran both efficiently and safely in this new configuration. The material that the crankshaft was made of had been upgraded so it had enough torque for 14 cylinders, but engineers also had to check if the engine had adequate structural strength and rigidity to withstand the new configuration.

The first 14-cylinder Wärtsilä-Sulzer RTA96-C two-stroke turbocharged diesel engine was produced in 2006 and entered commercial service that same year, aboard the Emma Maersk, the world’s largest container ship at the time.

As you can imagine, building such a large and complex engine is extremely difficult and resource-heavy, so it’s no wonder that RTA96-C engines cost upward of $25 million.