There are some double-acting diesels used for marine propulsion, and, as in the double-acting pistons of steam locomotives, a conventional crank mechanism, with

There are some double-acting diesels used for marine propulsion, and, as in the double-acting pistons of steam locomotives, a conventional crank mechanism, with the connecting rod connected to the piston rod outside of the cylinder, is used. Here, however, it seems they extract electrical energy by moving a magnet back and forth in a coil. https://www.instructables.com/id/Shake-Flashlight-1/ https://www.instructables.com/id/Shake-Flashlight-1/