This preview shows page 1. Sign up to view the full content.
Unformatted text preview: φ = Angle of inclination of the connecting rod with the line of stroke,
θ = Angle of inclination of the crank from top dead centre,
r = Radius of crank,
l = Length of connecting rod, and
n = Ratio of length of connecting rod to radius of crank = l / r.
We know that the force on the piston due to pressure of gas,
FL = Pressure × Area = p . A = p × π D2 /4
and inertia force of reciprocating parts, cos 2θ FI = Mass × *Acceleration = mR . ω2 . r cos θ +
n It may be noted that the inertia force of reciprocating parts opposes the force on the piston when
it moves during its downward stroke (i. e. when the piston moves from the top dead centre to bottom
dead centre). On the other hand, the inertia force of the reciprocating parts helps the force on the
piston when it moves from the bottom dead centre to top dead centre.
∴ Net force acting on the piston or piston pin (or gudgeon pin or wrist pin),
FP = Force due to gas pressure ∓ Inertia force
= FL ∓ FI
The –ve sign is used when piston moves from TDC to BDC and +ve sign is used when piston
moves from BDC to TDC.
When weight of the reciprocating parts (WR = mR . g) is to...
View Full Document
This note was uploaded on 09/30/2012 for the course MECHANICAL 403 taught by Professor A.thirumoorthy during the Spring '11 term at Anna University Chennai - Regional Office, Coimbatore.
- Spring '11