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Unformatted text preview: he bolts σt = Allowable tensile stress for the material of the bolts in MPa, and
nb = Number of bolts. Generally two bolts are used. = π
(d )2 σt × nb
4 cb Internal Combustion Engine Parts n 1155 Equating the inertia force to the force on the bolts, we have
( d cb ) 2 σ t × n b
From this expression, dcb is obtained. The nominal or major diameter (db) of the bolt is given by
db = cb
4. Thickness of the big end cap
The thickness of the big end cap (tc) may be determined by treating the cap as a beam freely
supported at the cap bolt centres and loaded by the inertia force at the top dead centre on the exhaust
stroke (i.e. FI when θ = 0). This load is assumed to act in between the uniformly distributed load and
the centrally concentrated load. Therefore, the maximum bending moment acting on the cap will be
MC = * I
x = Distance between the bolt centres.
= Dia. of crankpin or big end bearing (dc) + 2 × Thickness of bearing
liner (3 mm) + Clearance (3 mm)
bc = Width of the...
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- Spring '11