كلية الهندسة
قسم هندسة القوى الميكانيكية
Report in:
Presented to:
Dr.Eng.Awad Rashad
By : Mustafa Ibrahim Ali Abo elfotouh
Sec:7
Automotive engine Engines are desinged to be two strokes or four strokes of a piston that moves up and down in a cylinder. Generally, the automotive engine uses four strokes to convert chemical energy to mechanical energy through combustion of gasoline or similar hydrocarbon fuel. The heat produced is converted into mechanical work by pushing the piston down in the cylinder. A connecting rod attached to the piston transfers this energy to a rotating crankshaft Engines having from 1 to 16 cylinders in in-line, flat, horizontally opposed, or V-type cylinder arrangements have appeared in production vehicles, progressing from simple single-cylinder engines at the beginning of the twentieth century to complex V-12 and V-16 engines by the early 1930s. Increased vehicle size and weight played a major role in this transition, requiring engines with additional displacement and cylinders to provide acceptable performance.
Piston and cylinder geometry
B=bore, S=stroke, r=connecting rod lenght, a= crank offset , s= piston position ,
=crank angle,Vc=clearance volume,
Vd=dispalcement volume
Bore sizes of engines ranges from 0.5m down to 0.5 cm. The ratio of bore to stroke,B/S for small engines is usually from 0.8 to 1.2.
Stroke ratio
In a reciprocating piston engine, the stroke ratio, defined by either bore/stroke ratio or stroke/bore ratio, is a term to describe the ratio between cylinder bore diameter and piston stroke. This can be used for either an internal combustion engine, where the fuel is burned within the cylinders of the engine, or external combustion engine, such as a steam engine, where the combustion of the fuel takes place outside the working cylinders of the engine
Stroke/bore ratio is less common than bore/stroke ratio, but is used in some