General System Description

Turbocharging provides improved charging on the induction stroke, which produces more effective combustion of the mixture and an increase in power output. Effectively the engine achieves performance that is comparable to that of a larger engine, while maintaining the advantages of a smaller engine, Fig. 1.

Fig. 1 Turbocharger System:

Turbocharging is achieved by means of a turbo compressor. This unit utilizes the exhaust gases from the engine to drive the compressor. Exhaust gas flows through a turbine wheel mounted on the same shaft as the compressor impeller. Energy from the exhaust gas velocity is thus transferred to the compressor located in the induction system. The impeller acts on the inducted air causing an increase in charging pressure in the combustion chamber, Fig. 2.

Fig. 2 Turbo Compressor Operation:

This system increases torque at engine speeds during normal driving conditions, in contrast to those designed to increase performance only at full throttle. The turbine shaft rotates at high speeds and must be very accurately balanced. The shaft rotates in floating sliding contact bearings. These bearings utilize high pressure oil as the contact surface for the shaft. A special line supplies lubricating oil from the pump. Oil is returned to the sump through a large bore pipe. Sealing between the shaft and the bearing housing consists of sealing rings installed in grooves.
The system also incorporates an intercooler, reducing the temperature of the air between the turbocharger and the engine. As a result, the density of the inducted air increases, and the air admitted into the engine contains more oxygen. This allows more fuel to be injected and burned efficiently, increasing engine power. The air is cooled by approximately 110°F in the intercooler, which also reduces thermal stress on the engine.
The turbo unit is water cooled Fig. 3. This lowers temperature of bearing housing by about 212°F, reducing the chance of burned components.

Fig. 3 Water-Cooled Turbo: