🔍 Key Concepts

• Piston rod vs. connecting rod in a large low-speed crosshead diesel engine • Function of the crosshead and how it connects the reciprocating parts to the crankshaft • Difference between a pin (piston or crank pin) and a guide or sliding member

💭 Think About

• Trace the force path from the piston crown down to the crankshaft in the illustration: which component does the piston rod directly enter at its lower end? • Ask yourself which part moves in a straight line with the piston, and which parts rotate with the crankshaft. • Look at where the guides are located: do they hold a pin, or do they support a sliding block that another member fits into?

✅ Before You Answer

• Identify the part that moves only up and down and see what the piston rod is attached to at its lower end. • Confirm which components in the options are pins (pivot points) and which are sliding/guide assemblies. • Make sure you are not confusing the connecting rod attachment point at the crank with the attachment point of the piston rod shown near the top of the engine.