2. Turbocharger (see accompanying illustration) is a shaft, the central part of which is installed in a bearing. On both sides of the shaft there are turbines in two separate housings. One of the turbines is included in the exhaust tract, the other in the intake air duct. When the engine is running, the turbine included in the exhaust tract is driven by the flow of exhaust gases - while the rotation speed of the turbocharger shaft reaches 300,000 rpm, as a result of which the turbine installed at the other end of the shaft creates pressure in the intake tract. Due to the higher degree of filling of the cylinders, the increase in engine power can reach 100%.
3. The air pressure in the intake manifold during turbocharging increases by 0.4-0.8 bar (the total pressure reaches 1.8 bar), due to which the engine power also increases. The air pressure values in the intake air duct are determined by the boost pressure sensor, which transmits the corresponding signal to the electronic module of the engine management system. At the same time, the system monitors that the maximum air pressure does not exceed a certain value.
4. Along with power, the use of a turbocharger also increases engine torque, which has a beneficial effect on the smoothness of engine operation.
5. For optimal engine operation, a certain amount of air is required in different modes. Therefore, a turbocharger with variable turbine geometry is installed on the Z13DTH/Z17DTH and Z19DTH engines (VTG turbocharger), i.e. the guide vanes are smoothly controlled via an electromagnetic valve and a vacuum chamber. Thus, at any engine speed, optimum boost pressure is achieved.
6. The turbocharger bearing is lubricated under pressure in the general engine lubrication system. Oil is supplied and discharged to the oil pan through separate pipelines. The bearing housing has hermetic seals.
7. The turbocharger housing is attached to the exhaust manifold. To remove it, you need to disconnect all the supply connectors of the electrical wiring, fuel and oil lines, remove the exhaust manifold protection and the manifold together with the turbocharger. Then disconnect the turbocharger.
Note: If it is necessary to disconnect the cooling system pipes, the coolant must first be drained.
8. The turbocharger is a precision-made unit. Therefore, it cannot be repaired in a regular car service workshop and is replaced as a whole.
9. For maximum turbocharging efficiency, an intercooler is located between the turbocharger and the engine intake manifold (intercooler) (see Illustration 6.1, Part A), which cools the compressed air. Reducing the temperature of the inlet air leads to an increase in its density, an increase in the filling of the cylinders and the thermal efficiency of the working cycle.
10. The intercooler is installed on the radiator assembly of the cooling system, usually in front of it. To remove it, you need to dismantle the front bumper cover (see Chapter 11) and disconnect the air ducts and other supply lines.
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