In the scavenging system used in two-cycle engines, illustrated
in Figs. 6 and 7, 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
Fig. 7. Air Intake System Through Blower and
Engine (6V-53 Engine)
Several types of air cleaners are available for use with industrial engines. The light-duty oil bath air cleaner is used on most models.
However, a heavy-duty oil bath type or a dry type air cleaner may be installed where the engine is operating in heavy dust
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
The light-duty oil bath type air cleaner (Fig. 8) consists of a metal wool
cleaning element supported inside of a housing which contains an oil
reservoir. A chamber beneath the oil reservoir serves as a silencer for
the incoming air to the blower. Air is drawn into the cleaner by the blower
and passes over the top of the oil bath, where a major portion of the dirt is
trapped, then up through the metal wool, where the finer particles are
removed, and then down the central duct to the blower.
The heavy-duty oil bath type air cleaner (Fig. 9) consists of the body and
fixed filter assembly which filters the air and condenses the oil from the
air stream so that only dry air enters the engine. The condensed oil is
returned to the cup where the dirt settles out of the oil and the oil is
recirculated. A removable element assembly removes a major part of
the dust from the air stream thereby decreasing the dust load to the fixed
element. An inner cup, which can be removed from the outer (oil cup),
Fig. 6. Air Intake System Through Blower and Engine
acts as a baffle in directing the oil-laden air to the element and also
(In line Engine)
controls the amount of oil in circulation and meters the oil to the element.
The oil cup supports the inner cup and is a reservoir for oil and a settling
chamber for dirt.
Service the light-duty oil bath air cleaner as follows: