A two cylinder V-engine has the cylinders set at an angle of 45°, with both pistons connected to the single crank. The crank radius is 60 mm and the connecting rods are 300 mm long. The reciprocating mass per line is 1.5 kg and the total rotating mass is equivalent to 2 kg at the crank radius.

Question

A two cylinder V-engine has the cylinders set at an angle of 45°, with both pistons connected to the single crank. The crank radius is 60 mm and the connecting rods are 300 mm long. The reciprocating mass per line is 1.5 kg and the total rotating mass is equivalent to 2 kg at the crank radius. A balance mass fitted opposite to the crank is equivalent to 2.5 kg at a radius of 90 mm. Determine for an engine speed of 1800 rpm, the maximum and minimum values of the primary and secondary forces due to the inertia of reciprocating and rotating masses.

Accepted Answer

[latex] ext { Given: } \alpha=45^{\circ} r=60 mm , l=300 mm , R=1.5 kg , M=2 kg , B=2.5 kg , b=90 mm , N=1800 rpm [/latex].

[latex] \omega=2 \pi imes \frac{1800}{60} 188.5 rad / s [/latex].

[latex] B b=(M+c R) r [/latex].

[latex] 2.5 imes 90=(M+c R) imes 60 [/latex].

[latex] M+c R=4.75 kg [/latex].

[latex] ext { Primary force, } F_{P}=(M+c R) r \omega^{2}=4.75 imes 0.06 imes(188.5)^{2}=7994.7 N [/latex].

[latex] ext { Secondary force, } F_{S}=\left(\frac{\sqrt{3}}{2} ight)(M+c R) \frac{\omega^{2} r^{2}}{l} [/latex].

[latex] =\left(\frac{\sqrt{3}}{2} ight)(4.75)(188.5)^{2} \frac{(0.06)^{2}}{0.3}=1384.7 N [/latex].

Question 12.23: A two cylinder V-engine has the cylinders set at an angle of...

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