system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Car engines often have similar displacements for their configuration (ex. 2.0L I4, 5.0L V8). Why don't we see any manufacturers making large displacement I4's or small displacement V8's?
gpt
When the displacement gets bigger without increasing the cylinders, either the diameter or the stroke of the pistons has to increase. Too big a diameter makes it hard to have a controlled progression of the flame through the combustion area, and too big a stroke restricts the maximum rpm because of the stresses put on the con-rods, big ends and little ends when they change direction if they're travelling too fast. So more cylinders is better for large displacements.

As for having more cylinders for smaller displacement engines, it would simply add cost, with no benefit.