Fundamentals of turbocharging: Cleaning in operation for two and four-stroke engines

An Accelleron A200-H turbocharger to highlight turbocharger cleaning in operation
Maintaining your turbocharger and keeping internal parts clean is key to more efficient running. Here's everything you need to know about cleaning your turbocharger.

Turbocharging makes a huge difference to the efficiency of your engine, with the potential for ship owners and operators to save thousands of tons of fuel over an engine’s lifetime, while cutting emissions by hundreds of thousands of tons. Maintaining your turbocharger and keeping internal parts clean is key to more efficient running, so read on to find out everything you need to know about cleaning your turbocharger.

If you want to see the biggest efficiency savings when it comes to fuel and emissions, it’s critical that you maintain your engine and turbocharger as per manufacturer guidelines. For the turbocharger, that includes cleaning internal components after a specified number of operational hours. The number of hours will depend on fuel and application, but we’ve included some examples below.

Cleaning your turbocharger delivers plenty of benefits, including improved scavenge air pressure and lower exhaust gas temperatures, resulting in more efficient performance and a longer lifetime for parts.

Turbochargers that aren’t cleaned can see poor combustion conditions including incomplete combustion and ignition fail, along with carbon deposits and unburned fuel accumulation, which can all result in turbocharger fouling. In turn, this can lead to surging and premature wear or worse.

The cleaning process for turbochargers in operation depends on engine type, with two different types of cleaning – wet and dry. Wet cleaning involves spraying pressurized water, while dry cleaning uses tiny, pressurized granules made from carbon or other materials.

Wet cleaning is used for turbines on four-stroke engines, and dry cleaning for turbines on two-stroke engines. When it comes to cleaning the compressor, wet cleaning is suitable for turbochargers in operation on both two and four-stroke engines. 

Wet cleaning the turbine on four-stroke engines

You can wet clean the nozzle ring and turbine on turbochargers fitted to four-stroke engines across a wide engine load range.

It is critical that the engine load is reduced so that gases before the turbine are below 430 degrees Celsius, however. It’s also important to wait for the turbine to cool down before washing, and to wait for it to dry after cleaning, as this helps to reduce thermal stress in the material along with helping to prevent the possible formation of cracks.

The specified temperature limits for cleaning your turbocharger, along with stabilising times, have a direct influence on the lifetime of parts.

The cleaning of your turbocharger’s nozzle ring and turbine needs to be done after every 50 to 200 hours of operation, depending on fuel and application.

Dry cleaning the turbocharger nozzle ring and turbine for two-stroke engines

Dry cleaning the turbocharger nozzle ring and turbine on turbochargers fitted to two-stroke engines can also be performed across a wide engine load range, although it’s typically carried out at normal operation load.

Dry cleaning the turbocharger nozzle ring and turbine can result in surging, caused by a disruption of the airflow within the turbocharger and resulting in increased backpressure and turbulence, but when simply cleaning the turbocharger this is of no consequence.

Dry cleaning the nozzle ring and turbine requires the use of granules, which are injected into the turbine using a compressed air system. To dry clean the nozzle ring and turbine, blow through the pipeline to confirm the passages are clear.

Slowly relieve air pressure and add a measured quantity of carbon granules into the cleaning container as specified in the manual for your Accelleron turbocharger.

Then, use the compressed air to blow the granules into the turbocharger to clean the nozzle ring and turbine. The physical impact of the granules provides the cleaning action for the turbine. After you’ve cleaned the turbine, once again relieve the pressure in the container.

This cleaning needs to be done after every 25 to 50 hours of operation depending on fuel and application.

Cleaning the compressor during operation for two and four-stroke engines

Cleaning the compressor is a similar process for both two and four-stroke engines. The compressor is cleaned when the engine is running between 25 and 85% load and the turbocharger is running at high speed.

Water for cleaning is sucked through a special pipe arrangement, with the physical impact of the drops on the compressor providing the cleaning action. After cleaning, it’s important to wait for at least five minutes for the engine to dry before the engine is stopped.

This cleaning is done after every 25 to 100 hours of operation depending on application.

For all further cleaning details of different types, please refer to the respective manual for your Accelleron turbocharger.