If the piston reaches its upper limit of travel, what is it called?

If the piston reaches its upper limit of travel, what is it called?

• A. Top Dead Center
• B. Bottom Dead Center
• C. Mid Stroke
• D. Top Stroke

Answer: (B)

Piston positions in a cylinder have two extreme points: the top and the bottom. The upper extreme is the very top of the cylinder, where the connecting rod aligns with the crankshaft so the piston momentarily stops before turning around—that point is called Top Dead Center. It marks the end of the compression stroke (and, in a four-stroke cycle, the end of the exhaust stroke as well, depending on where you are in the cycle). The opposite extreme is Bottom Dead Center, which is the lowest point of travel. Mid Stroke is simply halfway between those extremes, and Top Stroke would describe movement toward the top but not the extreme.

Piston positions in a cylinder have two extreme points: the top and the bottom. The upper extreme is the very top of the cylinder, where the connecting rod aligns with the crankshaft so the piston momentarily stops before turning around—that point is called Top Dead Center. It marks the end of the compression stroke (and, in a four-stroke cycle, the end of the exhaust stroke as well, depending on where you are in the cycle). The opposite extreme is Bottom Dead Center, which is the lowest point of travel. Mid Stroke is simply halfway between those extremes, and Top Stroke would describe movement toward the top but not the extreme.