A turbocharger is an auxiliary component that helps to improve internal combustion engine power density and efficiency by recovering and reusing exhaust gases. This helps to make the engine it’s attached to considerably more efficient, with multiple benefits that include the ability to use a much smaller engine delivering the same power output as a naturally aspirated engine, better fuel consumption and a substantial reduction in CO2.

The turbine within your turbocharger recovers a part of the exhaust energy which would have been otherwise lost, by expanding exhaust gases around a rotating wheel. This turbine wheel is driven into rotation and its mechanical power is transmitted to the compressor, which vacuums fresh air from ambient and compresses it toward the engine intake receiver. This gives the engine a higher air mass per cycle.

When you start to drill down into the numbers, turbocharging can offer unbeatable value for customers. For example, turbochargers for two-stroke engines commonly used in container, tanker and bulker ships can provide up to 400% more power at a price that’s considerably less than 1% of the vessel’s cost. Turbochargers on both two-stroke and four-stroke engines can provide up to 75% of the engine’s power, despite equating to around 10% of the overall engine cost.

Using an example of an average 2,000 kW engine with a 25-year lifecycle at 50% load, CO2 emissions are likely to see a 14% decrease, with the ship owner/operator saving 23,000 tons of CO2 over 25 years simply by opting for a turbocharged engine. NOx emissions are reduced by 9%, at 2,900 tons compared to 3,200 tons.

Using an example of an average 2,000 kW engine with a 25-year lifecycle at 50% load, there’s a huge difference between turbocharged and naturally aspirated engines when it comes to fuel efficiency. The turbocharged version is likely to be around 14% more efficient, requiring 41,600 tons of fuel compared to 48,200 tons for the naturally aspirated version. This is impressive enough on a single engine and vessel but imagine the potential for fleet owners.

When properly maintained, turbochargers can last for decades, helping to make engines more efficient for the lifetime of your equipment. Global towage operator Svitzer has run some of Accelleron’s turbochargers on its fleet of 440 vessels for more than 30 years, and the Accelleron RR221-14 turbochargers aboard the Svitzer Sarah are a great example of what can be achieved when equipment is properly maintained, with the Accelleron RR turbocharger a mainstay of the marine world for an incredible 50 years.

While the principle of recovering exhaust gasses remains the same, not all turbochargers are created equal Two-stage turbocharging provides even more scope for efficiency than a traditional turbocharger, featuring two compressor and turbine stages rather than a single solution. The initial low-pressure stage feeds a high-pressure stage, enabling engine builders to increase compression ratios far higher. Thanks to the additional thermodynamic benefits of intercooling between both compressors, two-stage solutions such as Accelleron’s Power2 provide turbocharging efficiency above 75%, compared to 65% for conventional turbochargers.

It’s critical that a turbocharger matches your engine and requirements perfectly if you want the best results, and that’s where compressor maps come in. A compressor map basically shows the operating area of a turbocharger’s compressor, providing transparency over how the turbocharger is performing, and in turn enabling us to turn data into actionable insights. This can make a huge difference, whether it’s picking the best turbocharger for your requirements or ensuring the equipment you have is running properly and efficiently over its entire lifetime.

Alfred Büchi patented a ‘highly supercharged compound engine’ in 1905, describing an axial compressor, a radial piston engine and an axial turbine on the same shaft. The idea of using turbomachinery to recover exhaust energy to drive the supercharging compressor was born. Not long after, while Büchi was still making a name for himself, engineering pioneer Auguste Rateau began working with a company called BBC (Brown, Boveri & Cie) – which would eventually become the Accelleron you know today – to build and test some of the world’s first turbochargers.

Diesel engines can be split into three different types: High-speed, medium-speed and low-speed. So, what’s the difference? High-speed engines run at around 1200rpm or more and are generally found in smaller applications such as cars, trucks or construction vehicles, or powering generators. As the name suggests, medium-speed engines sit between high and low-speed engines, running at around 400rpm or more. These are often used in larger applications including smaller boats and larger electrical generators. Low-speed engines run at less than 400rpm and are most typically found in larger ships.