TM 5-3820-245-14&P
AIR SYSTEM
In the scavenging system used in two-cycle engines, a charge of air is forced into the cylinders by the blower and
thoroughly sweeps out all of the burned gases through the exhaust valve ports. This air also helps to cool the internal
engine parts, particularly the exhaust valves. At the beginning of the compression stroke, each cylinder is filled with fresh,
clean air which provides for efficient combustion.
The air, entering the blower from the air silencer or air cleaner, is picked up by the blower rotor lobes and carried to the
discharge side of the blower. The continuous discharge of 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 liner creates a uniform swirling motion to the intake air as it enters the cylinder. This
motion persists throughout the compression stroke and facilitates scavenging and combustion.
Air Cleaners
Several types of air cleaners are available for use with industrial engines.
The air cleaners are designed for fast, easy disassembly to facilitate efficient servicing. Maximum protection of the engine
against dust and other forms of air contamination is possible if the air cleaner is serviced at regular intervals.
The United Specialties dry-type air cleaner shown in Fig. 12 consists of a body, dust unloader and element clamped to a
base.
Air is drawn through the cleaner intake pipe and is automatically set into a circular motion. This positive spinning of the
dirty air "throws out" the heavier particles of dust and dirt where they are collected in the dust port and then expelled
through the dust unloader. The circular action continues even during low air intake at engine idle speeds.
Figure 7-10 - United Specialties Dry-Type Cleaner
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