Interpretation of relevant terms of the engine
Dead center: piston is connected with crank and rod assembly. The
piston has top and bottom limit positions in the cylinder. The top limit
position is called top dead center, which is the farthest from the
crankshaft centerline. The bottom limit position is called bottom dead
center, which is the nearest to the crankshaft centerline.
Piston stroke: The distance of piston movement from top dead center to
bottom dead center is called stroke. Cylinder working capacity: piston
swept volume in the cylinder when piston moves for a stroke.
Working volume of combustion chamber: the room that is between the
piston top and the top of the central combustion chamber of the cylinder
head when the piston is at top dead center
Total cylinder volume: the sum of cylinder working volume and working volume of combustion chamber
Compression ratio: an important structural parameter of the engine, which directly influence the power of the engine
Compression ratio(ε)= Total cylinder volume/ working volume of the
combustion chamber= 1+ cylinder working volume/ working volume of the
combustion chamber
In general conditions, for gasoline engine, ε=6~10