Which of the following does most to define the piston stroke dimension?

The piston stroke dimension is primarily defined by the crank throw dimension. The crank throw represents the distance from the center of the crankshaft to the center of the connecting rod's journal, effectively determining how far the piston travels up and down in the cylinder during one complete rotation of the crankshaft. This travel distance is what establishes the length of the piston stroke, which is a critical factor in the engine's displacement and overall performance.

Understanding this concept is essential because the piston stroke impacts the engine’s power output and efficiency. A longer stroke can increase engine displacement and torque, while also affecting the engine's operating characteristics and efficiency.

Other factors like clearance volume and connecting rod length do influence engine behavior and performance, but they do not directly set the piston stroke dimension. The swept volume relates to the total volume displaced by the piston as it moves between its highest point (top dead center) and its lowest point (bottom dead center) during the stroke, but it is the crank throw that directly dictates the length of that stroke.