General information
Turbocharger design (using the example of engine 603.971)
137a - Pneumatic actuator of the valve controlling the boost pressure; A - Intake air; B - Compressed air; C - Exhaust gases rotating the turbine wheel; D - Exhaust gas outlet; E - Turbocharger bypass valve; H - Pressure oil line; J - Return oil line; a - Turbocharger bypass valve; b - Rod; c - Compressor housing; d - Compressor impeller; e - Connection to the control line; a - Turbine housing; g - Turbine wheel; h - Turbocharger housing
The turbocharger is designed to increase engine power by increasing the air pressure in the intake manifold. Air does not simply enter the cylinders, but is supplied to them under pressure. In accordance with the increase in air supply, the high-pressure fuel pump increases the fuel supply.
Functional diagram of the boost control (engine 603.971)
B5/1 - Pressure sensor; 1 - Fuel injection pump; 103 - Aneroid compensator (ALDA); 110 - Exhaust manifold; 137 - Turbocharger; 137a - Pneumatic actuator of the boost pressure control valve; 138 - Intake manifold; A - Intake air; B - Compressed air; C - Exhaust gases rotating the turbine wheel; D - Exhaust gas outlet
The compressor turbine is driven by the exhaust gases. The gases pass through a special casing (compressor casing), are fed to the compressor turbine. The turbine rotates on a shaft, at the other end of which is a compressor wheel in a separate casing. It is this that supplies air under pressure to the pipeline.
An intermediate compressed air cooler is installed between the compressor and the pipeline (intercooler). In the intercooler, the air is cooled, compressing itself. The partial pressure of oxygen increases, which leads to an increase in engine power.
The air pressure in the pipeline is limited by a special sensor. When the maximum pressure is reached, the sensor opens the valve, thereby limiting the supply of exhaust gases to the turbine.
The compressor shaft is lubricated with engine oil, which is supplied through a specially designed hose. The shaft constantly "floats" in oil. From the compressor, the oil is discharged into the pan through the return hose.
The turbocharger is an integral part of the exhaust manifold and cannot be separated from it.
Precautionary measures
The rotation speed of the compressor turbines is enormous and the operating temperature is very high. In order to avoid injury and damage to the turbocharger, observe the following precautions:
- Do not start the engine after removing any turbocharger component. Foreign objects getting into the turbine blades can cause them to fail. You also risk injury from objects thrown from the turbine;
- After removing any turbocharger components or air intake hoses, cover it with a clean rag;
- Do not give gas immediately after starting the engine, especially if it is not warmed up. Oil cannot instantly lubricate the turbine shaft;
- Never turn off the ignition immediately after stopping the car. Do not press the accelerator pedal before stopping the engine. Immediately after turning off the ignition, oil stops being supplied to the compressor shaft and it will rotate for some time without lubrication;
- Before turning off the engine, let it idle for a few minutes, during which time the turbine speed will decrease significantly;
- Change the oil, oil filter and air cleaner regularly. Using old oil will cause deposits on the compressor shaft and cause it to fail. Before disconnecting the oil supply and return hoses from the compressor, thoroughly clean the surrounding surfaces. Store removed components in sealed containers.
For removal and installation, please also refer to Sections Removal and installation a turbocharger and Air blower - installation details.
Original material on the website MERCEDESMAN.ru