Advantages/Description; Advantages Description; Operation - Toro V Service Manual

ADVANTAGES DESCRIPTION
REED
VALVE
FIRST STROKE-
REED STROKE
EXHAUST GASES
751.2.5130.814
REED
CLOSED
VALVE
EXHAUST GASES
751.2.5130.815
Two-cycle engines have special advantages which
make their use more practical in certain applications.
Two-cycle engines are lightweight with an excellent
power-to-weight ratio and can be operated in any
position. They are also notably easy to maintain and
service because of their uncomplicated design.
The Toro Two-cycle V Engine used on Toro rotary
mowers is a reed valve design. This design name
describes the method used to control the admission
of the fuel/air mixture into the cylinder/crankcase
and combustion chamber, and the exhausting of
gases.
OPERATION
The two-cycle engine is one of the simplest and
most efficient power systems ever developed.
The illustration show at the left shows what happens
inside the engine during one full crankshaft
revolution. Fuel intake, fuel ignition and the exhaust
of burned gases all take place during a single
360-degree rotation of the crankshaft.
Beginning at a point where the top of the piston is
just below the exhaust port, the piston moves down
toward the crankcase. As the transfer port is
uncovered, the fuel/air mixture stored in the
pressurized crankcase is forced into the combustion
chamber.
Service Section
9-3