The Turbocharger is the core power component of a turbocharged engine,commonly known as the"turbine".It relies on the high-temperature exhaust gas energy emitted by the engine to drive and compress fresh air into the cylinder.Without increasing the engine displacement,it significantly increases the intake volume,allowing diesel combustion to be more complete,improving engine power and torque,and improving fuel economy.It is an essential component of modern excavator engines.

　　The entire assembly mainly consists of a turbine housing,turbine impeller,compressor housing,compressor impeller,intermediate housing,floating bearing,sealing ring,and pressure relief bypass valve.The engine emits high-temperature and high-speed exhaust gas,which drives the turbine impeller to rotate.The turbine shaft drives the coaxial compressor impeller to run synchronously at high speed,with a speed of up to tens of thousands of revolutions per minute.The compressor compresses the air and sends it to the intercooler before entering the cylinder to participate in combustion;The bypass pressure relief valve is responsible for limiting the maximum boost pressure to prevent engine damage caused by supercharging.

　　The floating bearings inside the turbine rely entirely on engine pressure oil for lubrication and heat dissipation.Pressure oil enters the intermediate housing of the turbocharger from the main oil passage,forming a very thin oil film between the bearing and the shaft.The shaft is suspended on the oil film and runs at high speed.After doing work,the oil flows back to the oil pan through the return pipe.Engine oil is both a lubricant and a cooling medium.Once the oil supply is insufficient,it can cause bearing erosion and shaft damage in just a few seconds.

　　It is divided into ordinary bypass valve turbine and variable cross-section VGT turbine.Many electronic fuel injection models in China III and IV use variable cross-section turbines,which optimize the turbocharging effect at different speeds by changing the blade angle and adapt to the emission after treatment system.The exhaust temperature under heavy mining conditions is extremely high,and the turbine is subjected to high temperature impacts for a long time;The load of earthwork conditions is relatively stable.

　　Many pilots only focus on insufficient power and ignore the condition of the turbine.Turbine failure can directly lead to power reduction,blue smoke and black smoke,and high oil consumption.The accessories of the turbine itself are expensive,and after the bearings wear out,they are mostly replaced directly with the assembly,which is difficult to repair.Familiar with the structure and working logic of the turbine,understanding the importance of engine oil to the turbine,can help maintenance personnel and operators identify early faults,avoid the expansion of faults and cause significant engine losses.