Lesson 2/Learning Event 2
The air entering the blower from the air cleaner is picked up by the blower rotor lobes and carried to the
discharge side of the blower. Continuous fresh air from the blower enters the air chamber of the cylinder
block and sweeps through the intake ports of the cylinder liners. The angle of the ports in the cylinder liners
creates a uniform swirling motion to the intake air as it enters the cylinders. This motion persists throughout
the compression stroke and facilitates scavenging and combustion.
FIGURE 18. CENTRIFUGAL SUPERCHARGER.
The centrifugal supercharger, or turbocharger, is a nonpositive-displacement type compressor of high output
capacity. The impeller is installed in the air inlet, is usually made of an aluminum-alloy forging, and is
designed to withstand high centrifugal forces of rotation. It is balanced accurately to reduce vibration. The
radial vanes of the impeller catch the air, and the air is centrifugally forced through the radial passageway
formed by the vanes.