Question

The crank and connecting rod of a reciprocating engine are 150 mm and 600 mm respectively. The crank makes an angle of 60° with the inner dead center and revolves at a uniform speed of 300 r.p.m. Find, by Klein’s construction,

1. Velocity and acceleration of the piston,

2. Velocity and acceleration of the mid-point D of the connecting rod, and

3. Angular velocity and angular acceleration of the connecting rod.

Answer 1

Note: Since D is the midpoint of AB, therefore d' is also midpoint of vector b' a'. Join o' d'. The vector o' d' represents the acceleration of midpoint D of the connecting rod i.e. aD.

By measurement, we find that aD = vector o' d' = 117 m/s²