Turbocharger Washing

1.   COMPRESSOR SIDE WET WASHING

• This is done at when the engine is at high load (80% load, turbocharger is at a higher rpm). Wet washing is done once every 24 or 48 hours. Based on the turbocharger, water is filled in a certain quantity while the valve is closed. Now when the valve is opened, water rushes into the turbocharger and washes it.
• Either a separate container is provided or a water gun is provided to perform this procedure. In both cases, quantity if water to be used is fixed (due to the cleaning device size). This is done at a comparatively higher load.
• A jet of water is used at high pressure to remove the carbon deposits. This procedure is called impingement.
• In case a separate container is provided, fill it completely with water and open valve to allow rapid movement of water into the turbocharger.
• In case water gun is provided, fill it with water and spray it inside the turbocharger.

2.   WET WASHING OF TURBINE SIDE

• This method is no longer in use because irregular washing causes imbalance and causes bearing wear damage.
• This is done at a reduced load. Desired rpm is provided in the manual.
• First the rpm is gradually decreased, and then then engine is kept running for some time to allow it to stabilize, as the turbocharger takes time to adjust rpm to that of the engine rpm. Water washing is carried out of 20 mins. After a few minutes, the load on the engine is gradually increased to higher rpm.
• To perform this procedure, the turbocharger drain is opened and a hose from fresh water hydrophore is connected via a reducing valve.
• When water goes into the turbocharger then for the first 5 minutes the water will evaporate. After a few minutes the turbocharger temperature reduces and carbon removal procedure begins. Carbon is removed by the process of Dilution. Normally this cleaning is done for 20 minutes.
• Then the Rpm is kept steady for some time and allowed to dry off the turbine. Then the load on the engine is gradually increased.

3.   TURBINE SIDE DRY WASHING

• This is also known as Grit washing. Size of grit varies depending upon the make of Turbocharger. Grit is made up of Walnut shells, and available in various sizes (1.5mm-2mm, 2.2mm-2.8mm). Size of grit that is to be used is provided in the manual by the manufacturer. Quantity of grit to be used is also specified (0.5kg, 1Kg etc)
• While performing grit washing, it is very important to use proper PPE kits (face shield) as the small particles move at a high velocity and can cause severe damage to eyes.
• Before starting grit washing, inform bridge to increase RPM (for higher rpm in turbocharger). The starting air line is to be drained as due to the moisture the grit particles could get stuck.

Close the valve 1 and 2, fill the grit into the chamber.After filling grit, close the valve 3.Then open valve 2, now the chamber is pressurised.Gradually open valve 1. Once all the grit is passed, a howling/whistling sound will come.

• If it is needed to carry out grit washing once again, use the same quantity of grit and do not reduce or increase the quantity of grit.
• Generally the air line is pressurized at 5-6 bar.
• If grit is not available, then broken grains of Rice can also be used. First the rice grains are passed through a sieve (chalni) so that only small grains can pass through it. However it is advised to do such procedure in case of emergencies only.
• After the procedure is completed close valve 1 and then 2.