Exhaust turbocharger is actually an air compressor that increases air intake through compressed air. It uses the inertial impulse of exhaust gas from the engine to push the turbine in the turbine chamber, the turbine drives the coaxial impeller, the impeller compressed the air from the air filter pipe to pressurize it into the cylinder. The increased air pressure and density entering the cylinder can burn more fuel, accordingly increase fuel amount and adjust engine speed, which can increase the output power of the engine.
Structure: Exhaust gas turbocharger is mainly made up of turbine and compressor.
Because the rotor of exhaust gas turbocharger has a high speed and the parts are more precise, so it is necessary to be familiar with the structural characteristics of the supercharger when using and maintaining it. Here, we will share the specific methods of cleaning and checking the exhaust gas turbocharger.
Cleaning of exhaust turbocharger
1. It is not allowed to clean all parts with corrosive cleaning fluid.
2. Soaking the carbon and sediment on the parts in the cleaning solution to make it soft.The thick carbon deposit on the side wall of the turbine end must be completely removed.
3. Only plastic scraper or mane brush can be used for cleaning or scraping the dirt on aluminum and copper parts.
4. If the steam impact cleaning is used, the shaft neck and other bearing surface should be protected.
5. Apply compressed air to clean the lubrication channels on all parts.
Inspection of exhaust gas turbocharger
Do not clean the parts before appearance inspection in order to analyze the cause of damage. The main parts to be inspected are listed below:
Floating bearing
Observe the wear of the end surface and the inner and outer surfaces of the floating ring. Generally speaking, after a long period of operation, the lead-tin layer plated on the inside and outside surfaces still exists, while the outer surface is larger than the inner surface, and there is a slight trace of wear on the surface of the oil groove, which is normal. The groove emitted from the working surface of the floating ring is caused by the unclean lubricating oil. If the surface is severely scraped or the measured wear limit is exceeded, it is recommended to replace the new floating ring.
Middle case
Observe whether there is any rubbing mark and coke deposit on the adjacent surface between the back of the compressor impeller and the back of the turbine impeller. If there is a spray phenomenon, the floating bearing has a large wear and the surface of the bearing inner hole is damaged, it is necessary to grind the inner hole with the corresponding grinding rod or gently wipe the inner hole surface with the metallographic sand skin to remove the traces of copper-lead materials adhered to the surface of the inner hole. It cannot be used until they are qualified by measurement. And analyze the cause.
Turbine shaft
Observe the wear of the carbon deposition at turbine end seal ring groove and the side wall of the ring groove; observe whether the inlet and outlet edges of turbine blades are bent or fractured; observe whether there is crack at the edge of the blade outlet and whether there is a curling burr caused by the rubbing at the tip of the blade; whether the back of the turbine blade is scratched or not.
Compressor impeller
Check the back of the impeller and the tip of the blade to avoid rubbing; check the blade for bending and breaking; check the edge of impeller inlet and outlet for cracking and scratching.
Vaneless turbine shell and compressor shell
Check the rubbing condition of the arc parts on each casing or whether there is scratch by foreign objects. Pay attention to observing the degree of oil deposition on the surface of each flow channel and analyzing the causes of the adverse conditions mentioned above.
Elastic seal ring
Check the wear and carbon deposit on both sides of the seal ring. When measuring the thickness and free state of the ring, the opening clearance should be not less than 2 mm. If it is less than the above value and the thickness of the ring exceeds the specified wear limit, it should be replaced.
Thrust piece and thrust bearing
There should be no obvious groove on the working surface, and check whether the oil inlet hole on the thrust bearing is blocked, and the axial thickness of each piece should be measured in accordance with the specified size range. If there are obvious wear marks on the working surface of the thrust plate and the wear limit is not exceeded, then another unworn surface of the two thrust pieces may be sequentially loaded as the working surface during reassembly.
Compressor end gas seal plate and middle shell
Check whether there is wear between the elastic sealing ring and the pedestal hole contact part at the turbine end elastic seal ring pedestal hole.
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