Question

Which of the following constitute kinematic link?

(A) Piston, piston rod and crosshead

(B) Connecting rod with big and small end bearings

(C) Crank, crankshaft and flywheel

(D) Cylinder, engine frame and main bearings

Choose the correct answer from the options given below:

• A. (A), (B) and (C) only
• B. (B), (C) and (D) only
• C. (A), (C) and (D) only
• D. (A), (B), (C) and (D)

Hint:

Recall the four links used to describe a slider crank mechanism in a reciprocating engine.

Answer 1

The Correct Option is D

Step 1: A kinematic link is a resistant body, or a group of parts rigidly fixed together, that has motion relative to another link in a mechanism.

Step 2: In the slider crank mechanism of a reciprocating engine, four such groups are usually identified as links.

Step 3: The cylinder, engine frame and main bearings are rigidly fixed to each other and do not move relative to one another, so together they form the fixed link.

Step 4: The crank, crankshaft and flywheel are rigidly connected and rotate together as a single unit, so they form the crank link.

Step 5: The connecting rod with its big end and small end bearings moves as one unit between the crank and the piston, so it forms the coupler link.

Step 6: The piston, piston rod and crosshead move together in a straight line inside the cylinder, so they form the slider link.

Since all four groups, (A), (B), (C) and (D), each qualify as a kinematic link, the correct answer is option 4.