What aspect of a piston’s stroke is associated with increased driving force levels?

The beginning of the stroke is where the piston begins to move from its rest position and starts to generate driving force. At this point, the piston is being accelerated from a standstill, and the combustion gases or other driving forces are applying maximum pressure to push the piston away from the bottom dead center. Here, the pressure from the combustion process or fluid is high, and the piston is fully engaged, leading to a rapid increase in acceleration and force.

In contrast, during the middle of the stroke, the piston has already gained momentum and is moving with a certain velocity, resulting in varying forces depending on the specific engine cycle or system dynamics. At the end of the stroke, the piston faces decreasing pressure as it approaches the end of its travel. This is typically where the driving force diminishes significantly as it reaches the point of maximum displacement.

Overall, the driving force levels are highest at the beginning of the stroke due to the combination of pressure application and the transition from rest to motion.