Basic Engine Theory - BOMBARDIER 1996 Ski-doo MX Z440 Handbook

BASIC ENGINE THEORY

TERMINOLOGY
Cycle : In a combustion engine, a cycle is accomplished when the four (4) phases;
intake, compression, ignition and exhaust are complete.
Top Dead Center: The position of the piston when it reaches the upper limit of
its travel inside the cylinder.
Bottom Dead Center: The position of the piston when it reaches the lower limit
of its travel inside the cylinder.
Bore : Diameter of the cylinder.
Stroke: The maximum movement of the piston from B.D.C. to T.D.C. It is characterized by
180° of crankshaft rotation.
Combustion
Chamber: Space between cylinder head and piston dome at T.D.C.
Displacement: The volume of the cylinder displaced by the piston as it travels from T.D.C. to
Bore* x Stroke x z = (X ~ ,
expressed in cc (cubic centimeters)
NOTE: To transfer cc to cubic inches, divide cc by 16.387
o
Compression : Reduction in volume or squeezing of a gas.
B. T.D.C. : Before Top Dead Center
A. T.D.C. : After Top Dead Center.
B. B.D.C. : Before Bottom Dead Center
A. B.D.C. : After Bottom Dead Center.
4
4 1 6 )
04-5