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The fundamentals of turbocharging

Turbocharging can revolutionize your engines, offering up to 400% more power than a naturally aspirated engine, along with significant savings when it comes to fuel and emissions. Read on, as we look at the fundamentals of turbocharging.

Turbocharging can revolutionize your engines, offering up to 400% more power than a naturally aspirated engine. Forced induction isn’t just about performance, however, with the potential to save up to 10% when it comes to fuel, and potentially even more when it comes to emissions. Read on, as we look at the fundamentals of turbocharging.

Perhaps surprisingly, the concept of forced induction – including turbocharging and supercharging – has been around for well over 100 years, and ABB Turbocharging has been at the forefront since the very beginning.

A turbocharger is an auxiliary component that helps to improve internal combustion engine power density and efficiency. To achieve this, the turbocharger turbine recovers a part of the exhaust energy which would have been otherwise lost, by expanding exhaust gases around a rotating wheel called a turbine wheel.

The turbine wheel is driven into rotation and its mechanical power is transmitted to the compressor, which vacuums fresh ambient air and compresses it toward the engine intake receiver. This gives the engine a higher air mass per cycle.

This additional boost can multiply the output power of an engine in comparison to a naturally aspirated engine, and can also result in substantial fuel consumption, CO2 and other emission reductions.

Turbocharging in numbers

It’s when you start to drill down into the numbers that turbocharging really makes sense, however, offering unbeatable value for the customer. 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.

Despite equating to around 10% of the overall engine cost, turbochargers on two-stroke engines can provide up to 75% of the engine’s power, supporting a power range of between 2,000 and 80,000 kW per engine.

The numbers are just as impressive when it comes to the four-stroke engines found in a much wider range of appliances, covering everything from ships to power plants and rail to construction machinery.

Once again turbochargers equate to around 10% of the engine’s overall cost, with the ability to provide up to 75% of the engine’s power. With four-stroke engines, turbochargers help to provide a power range between 500 and 20,000 kW per engine.

Huge savings for owner/operators

Such a boost in efficiency and performance is particularly apparent when it comes to selecting the best engine for a specific application. To achieve a similar power output, a naturally aspirated engine can be up to three or four times the size of its turbocharged equivalent, which has a cost in several different areas.

For example, while a naturally aspirated Diesel engine putting out 2,000 kW is likely to weigh around 110 tons on average, the turbocharged equivalent is a lot smaller, weighing an average 20-30 tons. That’s a difference of at least 73%, and the 80-ton or more saving alone will have an impact on efficiency.

« While a naturally aspirated engine putting out 2,000 kW is likely to weigh around 110 tons on average, the turbocharged equivalent is a lot smaller, weighing an average 20-30 tons »

There’s also a big difference when it comes to fuel efficiency. Using the same example of an average 2,000 kW engine with a 25-year lifecycle at 50% load, 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.

CO2 emissions see a similar 14% drop, 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.

Check out the full range of savings below

Manufacture and operation of a 2,000 kW Diesel engine(1)

Normally Aspirated Turbocharged Savings Savings (percentage)
Weight 110 tons 30 tons -80 tons -73%
Fuel consumption 48,200 tons 41,600 tons -6,600 tons -14%
CO2 emissions 167,500 tons 144,500 tons -23,000 tons -14%
NOx emissions 3,200 tons 2,900 tons -300 tons -9%

(1)Assumptions:
– 2,000 kW average engine output from over 200,000 ABB TCs in operation
– Lifecycle 25 years operation, 50% power demand

While turbochargers themselves are far from simple devices, with a lot of engineering knowledge and expertise going into their design and manufacture, the benefits really are easy for anybody to see.

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