To determine the state of balance of machines for primary and secondary forces can i have calculation and reading for this
Answers
The internal combustion engines convert the linear motion of the pistons to the rotational motion of crankshaft. This attributes to the primary and secondary forces in an engine. A single cyliner four-stroke engine completes two rotations of crankshaft per powerstroke and hence each cycle is given an angle of 180 degrees.
Primary forces - When a piston passes through TDC and BDC, the change of direction produces an inertia force due to which the piston tends to move in the direction in which it was moving before the change. This force, called the primary force, increases with the rise of the engine speed, and unless counteracted produces a severe oscillation in the vertical plane.
The piston showing a force F1 when it reaches TDC, gradually reverses direction and peaks to F2 on reaching BDC.
Secondary forces - In every cycle of 180 degree, the piston either moves from top to bottom or reverse. The distance travelled by the piston is not uniform and this give rise to the secondary forces. Secondary forces occur twice every half rotation and hence the name.
You could see that the distance moved by the piston by completing 90 degrees a little over the half stroke. Since piston is connected to the crankshaft and it rotates with uniform speed, the piston travels faster in first 90 degrees and slow in other half. The reverse happens while travelling from bottom to top.
On super imposing the primary and secondary forces, we can see the net forces acting on the engine.
You could see that in TDC both primary and secondary are adding up and in BDC they are negating.
Different number of cylinders are arranged in inline, horizontal and v-pattern to balance out these primary and secondary forces. Each having their own pros and cons.